Preheat your oven to 350°F (175°C) and grease a 9x5-inch loaf pan.
In a large bowl, mix pumpkin puree, light brown sugar, granulated sugar, vegetable oil, eggs, buttermilk, and vanilla extract.
In another bowl, combine flour, pumpkin pie spice, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the pumpkin mixture, stirring until just combined.
Fold in chocolate chips and pour the batter into the prepared loaf pan.
Bake for approximately 50-60 minutes, checking doneness with a toothpick.