The 22-year-old actor/singer was clearly smitten with the two hanging out together.
“These two… @oliviaculpo & my niece,” he captioned the pic.
Nick also posted a photo of him and his brother Joe snowboarding in Colorado, in addition to one of himself holding a snowball and a beer.
“Perfect snowballs,” Nick wrote. “Perfectly cold coors light. Perfect nights. Perfect way to finish the holiday break. #2015″