Begin by preheating your oven to 350°F (175°C). Prepare a 9x5-inch loaf pan by greasing it thoroughly with cooking spray or softened butter.
In a large mixing bowl, combine the pumpkin puree, packed brown sugar, granulated sugar, and vegetable oil. Blend until smooth and uniform in texture.
Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
In a separate bowl, sift together the all-purpose flour, baking powder, baking soda, salt, ground cinnamon, and ground nutmeg. Whisk to ensure even distribution.
Gradually introduce the dry ingredients into the wet mixture, stirring gently until just combined.
Gently fold in the semi-sweet chocolate chips and chopped walnuts, ensuring even distribution.
Pour the batter into the prepared loaf pan, spreading it evenly and smoothing the top.
Bake for approximately 55-60 minutes. Perform the toothpick test to check for doneness.
Once baked, remove from the oven and cool in the pan for 10 minutes before transferring to a wire rack to cool completely.
Notes
For an elegant touch, slice the cooled bread and dust the top with powdered sugar. Consider serving with whipped cream or vanilla ice cream.