Every Powder Blue I put in my tank was a nipper, and right now I have a Powder Brown (aka gold rim tang, white cheek, etc) that is also a nipper. He likes to pick on a purple plasma and milli colony, but nothing else.
I have angels and a pink tail trigger, and none of them touch anything.
You can never tell. It all depends on the individual fish.
Just my 2 cents.
Herb