Josh, you cannot nice her back. All being "nice" will do is make you look weak and unworthy of respect. Which means she won't be reattracted to you. Women's attraction follows respect.
I know. It's like instinct. I'm reflecting on two things I did today where instantly offered to do something nice so W wasn't inconvenienced. The positive is that not being nice is a healthy change for me and demonstrates a 180. My current WIP. Not to be so nice and to enforce more boundaries.