The original recipe called for the chocolate chips. While I like nuts in these, the rest of the family wants chocolate chips. Also, I usually use at least 1/2 cup whole wheat flour when I make them.
Note: if you have overripe bananas but you're not ready to use them, you can peel them, wrap them in plastic wrap, and put them into a zipper bag in the freezer. Then, when you're ready to bake muffins or banana bread, simply take out the desired number of bananas, unwrap, let sit out to thaw, and you're ready to go.