Preheat oven to 350 degrees Fahrenheit. Grease a muffin tin.
Combine wet ingredients in a small mixing bowl.
Combine dry ingredients in a large mixing bowl.
Add the wet ingredients to the dry and mix to combine.
Split the batter in half and place half in a separate bowl.
To one mixture, add the Part 2 ingredients: cocoa, milk, and chocolate chips.
Divide the pumpkin mixture evenly among each muffin tin, place ~1 Tbsp in each slot.
Divide the chocolate mixture evenly among each muffin tin, placing ~1 Tbsp on top of the pumpkin mixture already in each tin.
Using a butter knife, gently swirl the mixture together.
Bake for 20 minutes, or until a toothpick comes out clean.