The 'America's Got Talent' host and the superstar singer - who divorced earlier this year after eight years of marriage - have five-year-old twins Moroccan and Monroe together, and he was shocked when their daughter started talking about boys and saying she wants to walk down the aisle one day.
He said: "My daughter's a lot like her mom - loves to sing, loves to dress up. It's a lot of fun.
"She definitely likes boys, and I'm trying to sway her in a whole different direction. Like, last year she told me she was getting married. I was like, 'What!? You're four!' "
But Moroccan is yet to think about girls as he appears to be concentrating on his DJ career after landing a gig at a recent Halloween party the family attended.
Nick added: "My son is the biggest ham in the world and loves DJ-ing. He DJ-ed the Halloween party, rocking the mic. It was crazy.
"This party was the first time I was like, 'Man, do your thing.' And so he was scratching and talking on the mic. And he's seen me do it so much that he's got the hang of it. So I think he's gonna be taking daddy's job real soon."
Despite Nick and Mariah separating, the pair are still close for the sake of their kids, and he admits the former couple intend to keep it that way.
Speaking about spending holidays together, he added to PEOPLE: "I think that'll be something that we'll always embrace as a family and as our families expand.
"And continue to make sure that we keep everyone focused on love."
Mariah recently split from her fiance James Packer.