There's also dominance-related aggression. The cat orders you around, using language you understand (ie nip = give attention). It's typical for a dominant cat to ask (or demand) petting, then bite while you're petting it. Perhaps this is it in your case.
The ignoring will work well with this. If there are situations where you can't ignore her (ie at the dinner table, you still need to eat!), keep her out of the room for the time being. Teach her "sit," or even just to come to her food bowl, and make her do this before you set her food down. Pet her when you want to, not when she demands it, avoid petting along the spine, stop when you decide to but watch out for signals that she may want to bite.