Ludacris and Chrissy Teigen host the annual Billboard Music Awards, held this year at the MGM Grand Garden Arena in Las Vegas. The ceremony honors artists for the fan support they've garnered based on key fan interactions with music -- including sale... (more)s and radio airplay. Scheduled performers include Fall Out Boy, Wiz Khalifa, Hozier, Nick Jonas and Sam Smith. The nominees for the 2015 Billboard Chart Achievement Award -- the only fan-voted category in the lineup -- are Taylor Swift, Iggy Azalea and Meghan Trainor.