Backstreet's Back—all right! Actually, the No. 1 selling boy band in history has never really left. The Backstreet Boys, who will kick off a Las Vegas residency in March and a world tour after that, are currently pitchmen for Chex Mix in a series of ads that are dripping with glorious '90s nostalgia. Check out the video above to hear how the Chex Mix ads came about, how the group chooses which brands to work with, and which fellow '90s artists' marketing they admire.