The Eastern and Western conference finals begin Tuesday (8:30 p.m. ET, ESPN), with just four teams remaining in the fight for the NBA title.

Of those four teams, however, two made the playoffs through the play-in tournament.

The No. 7 seed Los Angeles Lakers, who advanced through the play-in tourney, will face the Denver Nuggets -- the No. 1 seed with the league's best record -- in the West. Meanwhile, the Miami Heat, who are the No. 8 seed via the play-in, take on the second-seeded Boston Celtics for a spot in the NBA Finals.

Jayson Tatum, Jaylen Brown and the Celtics outdueled league MVP Joel Embiid and the Philadelphia 76ers, as Tatum put together a historic Game 7 performance in the East semifinals. The Heat have been on an historic run of their own as the only 8-seed since 1999 to advance to the conference finals after defeating the New York Knicks -- and it's thanks to Jimmy Butler.

LeBron James and the Lakers are not done yet, defeating Stephen Curry and the Golden State Warriors in six games in the King's quest for another Finals run. The Nuggets passed their toughest test yet in felling a star-studded Phoenix Suns team that featured Kevin Durant, Devin Booker and Chris Paul.

Our experts break down the biggest matchups and storylines ahead of the conference finals, and they reveal what they're looking forward to most on basketball's biggest stage.

1. Which team are you most surprised to see in the conference finals?

Nick Friedell: The Heat. This team looked like it was on the brink of a retool just a few weeks ago. To see the turnaround they've made in such a short amount of time -- Miami trailed the Chicago Bulls in the final minutes of the East's final play-in matchup -- is one of the most unexpected runs I've seen during a decade and a half covering the league.

Kevin Pelton: The Heat, who are now tied for the best record in the playoffs (8-3) with the top-seeded Nuggets. After benefiting from atypically strong 3-point shooting in the first round (45%, easily best of any team), the Heat regressed to the mean in the conference semifinals (31%) yet still controlled the series against the Knicks.

Tim Bontemps: The Heat. They played the Milwaukee Bucks, the favorites to win the title, in the first round and dispatched them in five games. Now they are back in the conference finals against Boston for a third time in four years. The Lakers are also a remarkable story as the West's No. 7 seed, but the nod goes to the Heat.

Kendra Andrews: The Heat, who late in the season looked like they could be heading into a summer of major changes. Then "Playoff Jimmy" showed up. I don't think anyone expected them to be here.

Jamal Collier: The Nuggets. Maybe not entirely surprised -- cue Kevin Durant, "Am I surprised by the Nuggets?" -- but more impressed by the way they've gotten here. With the way Denver scuffled through the campaign's second half and with the bottom of the West standings unsettled, it would have been fair to think the Nuggets were most susceptible to an early-round upset. But the Nuggets have looked every bit as impressive and dominant as their place in the standings has suggested.

2. What duel are you looking forward to most in the Lakers-Nuggets series?

Andrews: Nikola Jokic vs. Anthony Davis. A lot can be said about the matchups Jokic has had to face against the Minnesota Timberwolves and the Suns throughout these playoffs -- and how he has had the clear edge in every one. That could arguably change in the West finals against Davis, another great big man who is leading the playoffs in blocks per game. How the Nuggets' two-time MVP adapts is a major storyline heading into Game 1.

Collier: Jokic vs. Davis. This will be Jokic's toughest test of the postseason in a defender who can guard him and a big man who will put pressure on Denver's interior defense. If Davis can be effective on both ends of the floor, the Lakers have a chance to win the series. But if Jokic can neutralize Davis or tire him out while chasing him around, the Nuggets should advance.

Friedell: Jokic vs. Davis. Jokic has the chance to prove to everybody just how good he is on the biggest stage. If he gets the best of this matchup, the Nuggets are headed to the NBA Finals.

Pelton: Jokic vs. James. Jokic won't be regularly defending James, but James and the Lakers will present a very different challenge for Jokic. Phoenix averaged just 46.4 points in the paint during the playoffs; the Lakers have averaged 50.3, second behind Denver. Predictably, the Nuggets weren't as good in the regular season against top-10 teams in paint scoring, beating them 59% of the time as compared to 69% against bottom-10 paint scoring teams like Phoenix.

Bontemps: Jokic vs. history. Jokic vs. James and Davis are heavyweight showdowns, but if Jokic can win another eight games in these playoffs, the "best player in the league" debate will be over.

3. What matchup are you looking forward to most in the Celtics-Heat series?

Pelton: Jayson Tatum vs. Jimmy Butler. The two versatile wings, like their teams, are meeting for the third time in the past four conference finals. Despite limited minutes midway through the series due to injury, Butler outscored Tatum last year; but Tatum had the better of both rebounds and assists, as he earned eight of the nine votes for series MVP (with Butler getting the other vote).

Collier: Tatum vs. Butler. Butler was a 3-pointer away from pulling off the upset last season. Miami seems way too undermanned to compete with Boston this year, and yet, you can't count out "Playoff Jimmy."

Andrews: Tatum vs. Butler. The Heat are here because of Butler. The same can be said for Tatum and the Celtics. Tatum has been tremendous this postseason and has come up huge for his team every time it needed him, including late in Game 6 and a remarkable Game 7 against the 76ers. The star who wins this one-on-one battle will win the series.

Bontemps: Butler vs. his body. For the Heat to have a chance in this series, Butler has to be the incandescent version of himself he was against Milwaukee. After spraining his ankle at the beginning of the Knicks series, he hasn't quite resembled that player. If Butler's body cooperates, he is good enough to make this series competitive.

Friedell: Butler vs. everybody. The Heat and Celtics are no strangers at this point in their recent playoff rivalry. Celtics coach Joe Mazzulla, just like Knicks coach Tom Thibodeau in the second round, will do everything he can to make somebody besides Butler beat them. Boston's second-ranked defense will make it tough, but Butler has shown he can raise his game on the biggest stage. It's going to be fun to watch ... again.

4. Who has been the playoff MVP so far?

Bontemps: Jokic, who averaged a 34-point triple-double while shooting 57% from the floor and 44% from 3 against the starry Suns. I believed coming into these playoffs that Jokic had more pressure on him than any player in the league, because it was time for him to deliver with a healthy roster and the top seed in the West. Not only has he delivered, he has done so in excess. It's been wildly impressive.

Friedell: Butler, who has given belief to a Heat locker room that appeared on the brink just a few weeks ago. Jokic's numbers are awesome, but Butler's team has come out of nowhere to reach this point, and Miami's season would have long since been over without him.

Collier: Butler. He has once again carried the Heat to the conference finals, this time past two higher seeds. Butler has been the best player on the floor the entire time.

Andrews: Butler. The Heat are not here without him. No ifs, ands or buts. Because of that, he has to be MVP so far.

Pelton: Devin Booker, despite Phoenix's elimination. Sure, Booker wasn't at his best as the Suns were ousted in a home blowout. But Phoenix might not have won a single game against Denver if not for Booker's historic Games 3 and 4, when he combined for 83 points on 34 of 43 shooting.

5. Who has the most at stake in the conference finals?

Pelton: In terms of historical legacy, James. Sure, other players would benefit from leading their teams to the NBA Finals, but they're young enough to have other opportunities. This might be James' last, best chance. Getting a team that looked headed for the lottery at the start of the season to the Finals would be another boost to his lengthy track record of playoff success.

Collier: James. Another Finals appearance at this stage of his career, during the season he broke the all-time scoring record, at age 38, and with the way this team looked earlier this campaign? Yeah, that would be another moment in the lore of King James.

Bontemps: Jokic. If he can lead Denver to a breakthrough Finals appearance, it would be a massive boon to The Joker's legacy and to the Nuggets franchise. There's a ton on the line for all of these teams, but a Finals trip would be truly groundbreaking in Denver.

Friedell: Jokic. He is an incredible player, but one of the biggest knocks on his game is that he has never been able to lift the Nuggets all the way through the postseason. What better way to end that narrative than to beat James and the Lakers.

Andrews: Nuggets coach Michael Malone. He has been with the Nuggets since 2015 and has been coaching the Jokic-Jamal Murray duo since 2016. If Denver doesn't reach the Finals as one of two teams remaining that didn't need the play-in tournament to advance, there could be questions about Malone's future and whether he's the guy to get it done in Denver.