here is a WaPo article explaining the situation:

After decades of holding sparsely attended caucuses, which sometimes got messy and chaotic, Nevada legislators passed a law in 2021 requiring primary elections whenever more than one candidate was on the ballot. After more than a dozen candidates launched campaigns for the 2024 Republican presidential nomination, Nevada officials scheduled a Republican primary for Tuesday.

But that 2021 law contained a big loophole.

“There has to be a primary, but the law doesn’t say how the party allocates their delegates” that who will count toward determining the winner of the Republican presidential nomination, said Rebecca Gill, a political science professor at the University of Nevada at Las Vegas.

That omission, combined with the intense lobbying of Nevada GOP leaders by former president Donald Trump, has led to a unique, and perhaps bewildering, scenario: Nevada this week will hold a state-run primary and party-run caucuses.

TL;DR: Nevada made a law to make the it easier for citizens to participate in the “select your party’s nominee” process, but it was written kinda poorly and has a huge loophole clearly contrary to the intent of the law, which the GOP is of course exploiting.

There’s not a lot to do in Nevada beyond gambling and hookers.