I am sorry that you are having such a hard time. However, did you approach this person or did you go straight to the NM? If someone tattled on me without giving me the benefit of a face to face explanation first, I'd be pretty mean too.
There are unpleasant people everywhere and you need to develop a thick skin. As a professional, you are expected to resolve interpersonal conflicts yourself without your self-esteem being crushed, or the NM doing the dirty work for you.
I've only been a nurse for three years, but I've been a human being and a professional (nursing is a second career for me) for waaaay longer than that. You really have to try and not take things personally. It's hard to do, but you will be much happier in the end.