Preheat oven to 350 F, and prepare the muffin tin with liners or a non-stick cooking spray.
In a large bowl, mix together the pumpkin puree, brown sugar, egg, and vanilla extract.
In a separate bowl, mix together the flour, oats, spices, salt, and baking powder.
Combine the two mixtures in one bowl, and fold in the chocolate chips.
Fill 3/4 of each muffin tin with mixture, and bake for 20-23 minutes until cooked through.
Let cool for 20 minutes before removing to serve.