I'm not that keen on it and it's quite dated here (Britain). It was VERY popular in the 70s and 80s. There were four in my year at school. I don't know anyone called
Nicole but it is reasonably popular for young children. Personally, I hate it.
Some of the
Nicolas I have known only go by
Nicola others are
Nicky, Nicki,
Nikki or Niki. It's one of those nicknames that has a number of different spellings.
I have never seen
Nikola and don't like it. I've seen
Nichola as an alternative spelling which I prefer.