Nevada is a state that does not allow candidates to use political party designations on the ballot. However, the state has had a long history of political parties, with 22 different parties having been established over the years. Of these, only six have lasted until the 2004 elections. Currently, the two major parties in Nevada are the Democratic Party and the Republican Party.
The Democratic Party has a formal set of statutes that form its structure, and they control five of the six state offices, a majority in the Nevada Senate and a majority in the Nevada Assembly. Democrats also hold two seats in the United States Senate and three of the four in the state. In the 2020 elections, Democratic Senator Catherine Cortez Masto won her second term representing Nevada, defeating Republican Adam Laxalt to take control of the house party for the next two years of Joe Biden's presidency. With Mark Kelly's victory in Arizona on Friday, Democrats now have a 50-49 advantage in the Senate.
The party will retain control of the chamber, regardless of how next month's runoff elections in Georgia unfolds. Cortez Masto is the first Latina woman to be elected to the Senate, and despite an influx of national Republican groups spending on attack ads, she managed to secure her re-election bid. It was not yet clear which party would control the House of Representatives, as the count continued in very tight races in California and some other states. The state of Nevada is one of the most diverse in the country, and its population is mostly working class. They have had to deal with both inflation and the repercussions of the shutdown of Las Vegas' tourism-based economy during the COVID-19 pandemic. After the 1906 elections, the Democratic and Republican parties became Nevada's two major parties. Although there are hundreds of political parties in the United States, only a few qualify for their candidates' names to be printed on ballots.
For more information on ballot access requirements for political parties in Nevada, see this.