With five weeks left in the regular season, NBA analysts are still struggling to gauge whether the Nuggets are bona fide championship contenders.

Perhaps the biggest reason: Few expected Denver to challenge for a No. 1 seed so quickly. Less than a year removed from barely missing the playoffs, the Nuggets enter Friday night’s game against Golden State at Oracle Arena with a chance to tie the Warriors for the top spot in the Western Conference.

“I really like what they’ve done, and obviously this year they’ve had a fantastic season — probably ahead of where most people would’ve picked them,” Warriors head coach Steve Kerr said. “I think it was easy to see where they were heading and that they were a playoff team, but yeah, they’ve probably even exceeded expectations.”

The Nuggets (43-21) are 3½ games up on Oklahoma City (40-25) and four games ahead of Houston (39-25), but many assume that the Thunder and Rockets would test Golden State more in a seven-game series than Denver. Is that a fair assessment? Why isn’t the Nuggets’ regular-season success being taken more seriously?

The case for Denver being the Warriors’ biggest threat in the West:

With a fifth-ranked offense and an 11th-ranked defense, the Nuggets are one of the NBA’s most balanced teams. The Bucks, who are a league-leading 49-16, are the only franchise ahead of Denver in both categories. Not since the 2005-06 Heat has a championship team not boasted a top-11 offense and defense.

The Nuggets — like many clubs — prioritize ball movement and 3-point shooting, but what makes them so tricky to defend is that they run their offense through the 7-foot, 250-pound Nikola Jokic. The 24-year-old is on pace to join Wilt Chamberlain, Oscar Robertson and Russell Westbrook as the only players in NBA history to average at least 19 points, 10 rebounds and 7.5 assists in a season.

Remarkably versatile for his size, Jokic is highly efficient off the dribble, out of the post and as a shooter. His ability to break down defenses and find open looks — for himself, as well as others — has helped him rank fifth in the NBA with an offensive real plus-minus of 4.70.

The playoffs, even more than the regular season, hinge on mismatches. Jokic might be the biggest mismatch this side of Joel Embiid or Giannis Antetokounmpo.

Though not particularly special defensively, Jokic has done a better job this season hiding his weaknesses on that side of the ball. Jokic, who was long targeted on pick-and-rolls, has been moved up on that critical defensive sequence to put more pressure on the slew of capable defenders behind him.

Outside of Toronto, Denver might be the deepest team in the NBA.

Jamal Murray is one of the league’s best young point guards. The Nuggets have hit later in the draft to surround Jokic and Murray with important complementary pieces like Gary Harris (No. 19, 2014), Juan Hernangomez (No. 15, 2016), Malik Beasley (No. 19, 2016), Monte Morris (No. 51, 2017) and Torrey Craig (undrafted, 2014). By signing four-time All-Star Paul Millsap in July 2017, the NBA’s youngest team got a much-needed veteran presence.

The case against Denver being the Warriors’ biggest threat in the West:

The Nuggets have a promising core, but they might need a year or two of seasoning before they’re ready to contend for an NBA title. This is a team that hasn’t reached the playoffs since 2013 and hasn’t escaped the first round since 2009.

Seldom do teams go from the lottery straight to the conference finals or NBA Finals. In the two years before it won the 2014-15 championship, Golden State exited in the first and second rounds.

Houston, which returns many of its key contributors from the group that pushed the Warriors to the brink in the 2018 West finals, has won six games in a row behind dazzling performances from James Harden. Meanwhile, Oklahoma City is as loaded as it has been since it had Kevin Durant.

Though the Thunder is mired in a 2-5 rut, it boasts a former MVP (Westbrook) and a player who could win both MVP and Defensive Player of the Year this season (Paul George). It’s difficult to imagine Denver outdueling Oklahoma City — or Houston, for that matter — in a seven-game series.

However, much of this might come down to seeding. If the Rockets and Thunder have a more daunting path to the conference finals than the Nuggets, Mike Malone’s team could extend its feel-good narrative deep into the postseason.

Connor Letourneau is a San Francisco Chronicle staff writer. Email: cletourneau@sfchronicle.com. Twitter: @Con_Chron