Basically, put chicken, celery, and nuts (I like walnuts, but pick your fave) through a food processor, add mayo and salt and pepper to taste. You can also add broth, but since you're using leftover rotisserie (and don't have broth due to cooking the chicken), it isn't necessary. It's easy and deeeee-lish.
I meant to say that you can throw so many things in chicken salad, so that is my basic recipe, but you could add:
-whatever spice you like... a little curry, some garlic, whatever you fancy