1) a hipster, literally a young person enamored with Nico, the singer for The Velvet Underground, a somewhat obscure, critically adored 60's protopunk band from New York.
2) an adolescent girl obsessed with handsome men, or Nicos.
Arnold: You know, Bat for Lashes, Dirty Projectors, and some older stuff too, like Iggy, early Bowie, New York Dolls, Scott Walker, and, of course, The Velvet Underground.
Sara (to Fred, as Arnold walks away): I don't know any of the bands he was talking about.
Fred (laughs, noticing Sara checking Arnold out): That's because he's a nicoteen. And I think you might be too.