According to a source, Carter was supposed to attend his sister Angel's wedding to boyfriend Corey Conrad in California but he celebrated a joint bachelor party with his girlfriend in Las Vegas instead, reported Us magazine.
Nick and his girlfriend Lauren Kitt, who got engaged last year, reportedly partied at the Palms Hotel with a group of about 15 friends.
Nick had tweeted a day before, "It's about to go down at @palms just entered the room of ecstasy."
A photo of gift bags for his friends was attached to the post. He also added a photo of him and his friends, with the caption, "Bad boyz at the bachelor party. @palms @ghostbarlv#gbdc."