The show includes categories like "must-follow artist on Twitter" and "best fan cover." Fan voting will decide the awards. MTV says 1.9 million votes have been cast.
At the Vegas event, rapper Chidera "Chiddy" Anamege of the hip-hop group Chiddy Bang will try to enter the Guinness World Records for longest freestyle rap.
Other scheduled performers will include Lupe Fiasco, Lil B, Matt & Kim and Mumford & Sons.