If you took general biology, review your notes from that class. If you didn't, read the first few chapters or so of your A&P book, which are a review of general bio. I remember on the first day of my A&P I class, we had to take a general bio quiz to make sure we were prepared for the class. I dunno if your school requires anything like that though, but it's something to be aware of. You could also study anatomical terms, like medial/lateral, superior/inferior, etc. - there should be a chapter in your A&P book that includes this and basic organization of the human body. But honestly, I'd try not to stress too much.
Nutrition is very easy and there isn't much you would need to do before class starts. There's some general bio and chem involved, but it's very basic, and most likely the prof will explain it anyway because there'll be people in the class that don't know it already. If you want to review basic chemistry - structure of carbs, proteins, etc., and chemical bonding, you could do that I guess.