Preheat the oven to 400°F. Place 12 cupcake liners in a muffin tin. Set aside.
In a large bowl whisk together the flour, baking soda, baking powder, cinnamon, pumpkin pie spice and salt.
In a separate large bowl whisk together the granulated sugar, brown sugar, oil, eggs, vanilla extract, sour cream and mashed bananas.
Add the wet ingredients into the bowl with the dry ingredients and stir with a wooden spoon until the dry ingredients are just combined. Gently fold in the walnuts and chocolate chips. Divide the batter evenly into the muffin tin.
Put the muffins into the oven and immediately reduce the oven temperature to 375°F. Bake for 25-30 minutes, until the muffins are golden brown and a toothpick inserted into the center of the muffins comes out clean.
Let muffins sit in the pan for about 5 minutes before removing to a cooling rack. Serve warm.