I think Nicole has tried to carve out a career in the US but for one reason or another it doesn't seem to have worked.
She wasn't very popular on US X Factor and her music career never really took off.
I always thought she was quite dull and boring until her judging role on X Factor now I quite like her. She seems to have a good sense of humour and the UK (for the most part!) seem to have taken to her.
I don't think she will be around for much longer though, at least as a pop star, as nice as she is I still think she's missing that spark.