It's cute, though I prefer it as a NN rather than a given name. One of my closest friends has a son named Nico, not short for anything.
I like it best as a NN for Nikolai, but it could work for any Nic/k- name.
Nicholas
Nicole
Nicola
Nicolette
Nikita
Etc.
I think it could work for a boy or a girl, though knowing my friend's son, it comes off a bit more as a boys name to me.