Preheat oven to 425 degrees F. Spray muffin pan with cooking spray or line with muffin liners and set aside.
Add flour, baking powder, salt, cinnamon and nutmeg to a mixing bowl. Whisk to combine.
To another mixing bowl, add eggs and sugars and whisk to combine well. Whisk in buttermilk, oil and vanilla extract until mixture is pale.
Gently fold the dry ingredients into the wet and mix together gently using a wooden spoon or rubber spatula. Be careful not to overmix.
Batter will be thick and have lumps.
Stir in chocolate chips.
Spoon batter into prepared muffin pan, filling the cups all the way up to the top.
Bake at 425 degrees for 5 minutes, then leave the pan in the oven and reduce oven temperature to 375 degrees F. Continue to bake another 13 minutes, until a toothpick inserted in the center comes out clean (other than possible melted chocolate).
Let cool in the pan for 5-7 minutes, then remove to a wire cooling rack.