Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine 1 cup of pumpkin puree, ½ cup of vegetable oil, ½ cup of brown sugar, and 2 large eggs. Beat them together until well combined.
In another bowl, whisk together 1 ½ cups of all-purpose flour, 1 tsp of baking soda, and 1 tsp of cinnamon.
Slowly fold the dry ingredients into the wet mixture, being careful not to overmix.
Gently fold in ½ cup of chocolate chips.
Prepare your muffin tin by lining it with cupcake liners or spraying it with non-stick cooking spray.
Fill each muffin cup about ¾ full with batter.
Place in the preheated oven and bake for about 18-22 minutes, or until a toothpick inserted comes out clean.
Allow your muffins to cool in the pan for about 5 minutes before transferring them to a wire rack to cool completely.