Am only guessing that she is in a very short arc......could be wrong, but Nicole is returning at some point in very short arc, so it IS being done.
I do agree the writing for her last round was not good at all, she came across very bland. But then she did not have much to do except check on Rafe in his coma for weeks, until he finally came out of it, then a few days of urging him on in his therapy. It just seemed like she was hired, and they did not know what to do with her. It was after she was there a while, before it was revealed she was Ben's sister.