Nuts contain, I believe, mostly monounsaturated fats, meaning they'll lower your LDL (bad) cholesterol and raise your HDL (good) cholesterol, and they'll be easy to burn for energy purposes.
They also contain some complex carbohydrates and protein.
If you get nuts, avoid salted nuts, and make sure your peanuts are as fresh as possible (because they've found that microscopic mold grows on peanut oil that is carcinogenic).