The rapper and reality TV star went public with their relationship in March.
Kardashian married NBA player Kris Humphries in August 2011 and their divorce is not finalized.
West's Sunday-night show was his third consecutive performance at Revel. He took the stage for nearly two hours, performing hits like "Good Life," ''Jesus Walks" and "Clique" in an all-white ensemble with two bandmates.
Kardashian is expected to spend New Year's Eve at public appearance at a Las Vegas nightclub.
AP Writer Bianca Roach contributed to this report.
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