Preheat oven to 350°F. Lightly grease a 9 x 5 inch loaf pan.
In a medium mixing bowl, whisk together flour, baking soda, cinnamon, nutmeg (if using), and salt.
In a large mixing bowl, whisk mashed bananas, oil, both sugars, egg, and vanilla extract until well-combined.
Add dry ingredients to wet and stir just until combined. Fold in chocolate chips.
Bake for 50-60 minutes, or until a wooden tester (or toothpick) inserted into the center of the cake comes out clean. Let sit in pan for 10 minutes before turning out onto a wire rack to cool completely.