Lori P. - how did your morning go?
One little piece of unsolicited advice - next time you interact with Nan AFTER you believe HR has spoken with her, be aware of her attitude. And if it appears she has it in for you moreso than before you took your concerns to HR, just a simple statement from you might be powerful...
"Gee, Nan, I sure would hate to think that my talking to HR the other day has anything to do with your current attitude towards me...?"
Imperfect does not = unsuccessful