Nick, 32, told InTouch magazine: "(She) does everything everyone else does.
"You can definitely have a family of two people, but when you create humans together, it changes things. It's brought us even closer together. Being parents creates a whole different dynamic; you make different decisions. But it really solidifies what a family is all about."
The 'America's Got Talent' host also revealed that his glamorous wife is very low maintenance when she isn't working but always likes her hair to look good.
He said: "No. But she doesn't ever wear that much makeup on TV - it's all about the hair for her. But at home, she's always just chillin' with no makeup and her hair tied up. I mean, you just can't be dolled up 24/7. Besides, she's my wife, she really doesn't need to be dolled up for me."
Nick recently admitted he is a strict parent to the twins.
He said: "My kids - it's a blessing - they're extremely disciplined. They try [misbehaving] with other people because everyone gives them so much attention, but when it comes to my wife and I, we only have to say something once.
"We ask them to have a seat, they sit down, cross their legs and put their hands in their lap. I hope it lasts!
"I've got the loudest voice in the house, so they've always responded to that ever since they were newborns. They hear my voice and they freeze."