Preheat oven to 350F. Grease muffin pan(s) or line with muffin papers. Mix flour, sugars, baking soda, baking powder, and salt in a large bowl. In another bowl, break eggs and add pumpkin and butter. Stir rapidly until well blended. Stir in chocolate chips. Pour over dry ingredients and fold in. Do not over mix. Scoop into pan and bake 20-25 minutes. They should still seem a little underdone when removed from the oven – test with a toothpick.