Denver Nuggets forward Michael Porter Jr. is making the most of his team's trip to L.A. ... hitting up Rodeo Drive with Kelsey Calemine and checking out some luxury watches!!

The couple was spotted at the ‭Rolex Boutique Gearys‬ around 5 PM on Tuesday ... one day before the Nugs face off against the Los Angeles Lakers.

MPJ -- who has been linked to the model and influencer for nearly a year -- tried on some expensive timepieces during the visit ... and we're told Calemine got in on the fun, too.

For those unfamiliar, Calemine is quite popular on social media ... with more than three million followers across all platforms.

She previously dated EDM artist Marshmello ... and MPJ was notably linked to two Madisons -- Pettis and Prewett.

No word on what exact accessories the two left with ... but MPJ has reportedly made about $115 million in the NBA since getting drafted back in 2018, so no need to ball on a budget.

As for his on-court action, Porter Jr. is averaging more than 16 points a game for the Nuggets ... who look primed to make another deep playoff run this season.