The 'Jealous' singer is smitten with beauty queen Olivia Culpo - who he has been dating for 18 months - and would love to make their union official one day.
Speaking on 'Access Hollywood Live', he gushed: "I met her at a Fashion Week party a couple years back. It's been an amazing year and a half now. She's the best."
Asked if he is considering marriage, he added: "At some point. It would be ideal [to settle down], but we're still quite young and we're going on a journey."
Nick, 22, has recently been showing off his muscular physique and though it "feels good" to be in such great shape, he insists he doesn't spend his time admiring his buff body.
He said: "In a way, I feel like it was a combination of things, just getting older, growing up and then shooting this TV show 'Kingdom'.
"It feels good to feel healthy, but I'm not sitting there looking in the mirror."
The former Jonas Brothers singer recently launched a solo career and is excited about releasing his self-titled album as the response to his single 'Jealous' has been "incredible".
He said: "I'm thrilled to have music that I'm so passionate about that I love.
"The response to 'Jealous' has been incredible and I'm ready to get the whole thing out there!"
It was recently claimed Nick was planning to propose to Olivia by the end of this year.
A source said: "Nick has told everyone that he wants to spend the rest of his life with her. They are obsessed with each other and he has even said that he wants to ask her to marry him by the New Year!"