Preheat the oven to 325. In a large bowl combine flour, baking soda, baking powder, nutmeg, cinnamon, and salt.
In another bowl pour sugar, vegetable oil. Add the first egg and mix until completely combined. Add the second egg and mix well, then the third egg. Mash up the banana's and pour into the wet ingredients, mix for a few minutes.
Add the dry ingredients to the wet about one cup of dry ingredients at a time and mix well. Once everything is combined add the chocolate chips and walnuts. Mix for a few minutes. Pour the mixture in a greased bread pan and bake for about an hour. This mixture is really thick so the baking time could be more then an hour depending on your oven. Stick a knife in the middle of the bread to see if it's done.