So she is already doing well for herself, especially as she admits she has had to overcome shyness.
The blonde bombshell will support rap kings Rizzle Kicks at the O2 Academy tonight, but playing to thousands of people has not come easy.
"At primary school I was so shy I couldn't even speak to anybody," says Nina.
"Then, in the last year of primary, I sang a song at a talent show, and thought to myself 'I quite enjoyed that'. I guess I was quiet in secondary, too, until I made friends, but I was painfully shy before that.
"Off stage, I am still quite like that whenever I meet anyone new, although as an artist I get more outgoing with the crowd."
Nina has had to learn fast how to adapt to larger crowds, though.
Although she started gigging only last year, she has already played some massive shows, winning over audiences with a pop-rock combo that adds a dash of Sheeran-style lyrics and a sprinkling of Laura Marling-esque emotion on top.
Yet it has been quite a step for her, as she plays on stage alone.
"It's definitely been coming a long way," says Nina, who had a cameo in Ed Sheeran's Drunk video.
"Going around Europe with Example was really good for me because each country was very different for me in comparison to a British crowd.
"It was great working out how to play to them, and the Arena tour was something I could never do on my own, so supporting him there was really big for me.
"His fans are all into dance music, so I had to make a good impression right away."
Half Swedish and half Scottish, Nina released her first proper single with Boy last month, following on from the Apple Tree EP that came out over the summer and reached No 6 in the iTunes charts.
Now she is writing material for her debut album, including a collaboration with Fraser T Smith, who had previously worked with Adele, a singer Nina admires.
However, the singer is strong-minded enough to want to work on her own for the most part, rather than with established hit-makers.
"Fraser was really cool to work with, but I prefer to write by myself," she says.
"A lot of the co-writes I have done have not worked out, because I am so used to writing on my own.
"Writing with other people, sometimes you just do not click so it is just about trying to find people that you can work with.
"If it is your song and you are singing it, it is weird to be singing about someone else's feelings.
"Co-writing is more useful from having ideas about instruments, but I love the words, and I want to make sure they mean something to me."
That means that while there is certainly some pop melodies at play in her material, there is little chance of Nina deciding she is going to chase chart success and start copying other chart stars.
"I am only 18, so by the time I am 21 I might have a different approach to things but I could never see myself being like Jessie J," she says.
"I will always be playing an instrument."
Her down to earth style means she has already won a large fan base of youthful followers.
And Nina does not want to let them down with how she acts.
"I do try and set a good example," she says. "I have had young girls Tweet me saying I am an inspiration and a role model and that is a really sweet thing to hear."
NINA is also hoping her album, due out early next year, enjoys similar sweet success.
Although she is on the books of the Island label, she says everything is still relaxed.
"There is a little bit of pressure, but because I had been doing things independently for a year, it gave me confidence and reassurance that I could make the record I wanted to make," she says.
"Island have not tried to change me into someone I do not want to be, it is just having a bigger support behind what I am already doing."
And she is hopeful of getting some strong support when she plays at the Rizzle Kicks gig tonight.
"Rizzle Kicks might be a different style, but a lot of their crowd are of a similar age," she adds. "I think some of my fans will be going to see them anyway, so it should be good."
l Rizzle Kicks and Nina Nesbitt, tonight, O2 Academy, sold out, 7pm.