Preheat the oven to 325℉, then grease and line a 9x5 inch loaf tin with baking spray and parchment paper.
In a medium-sized bowl, whisk the flour, cinnamon, pumpkin pie spice, baking soda, and salt until combined.
Whisk together the vegetable oil, sugar, brown sugar, and pumpkin purée until homogeneous. Add the eggs and vanilla extract, then stir until smooth.
Add ⅓ of the dry ingredients to the pumpkin mixture and fold until just combined, then add in ½ of the whole milk and mix. Continue alternating the dry and wet ingredients in three additions, being sure to end with the dry mix.
Right before all of the flour is incorporated, add in the chopped chocolate and fold until just combined. Pour the batter into the prepared pan and top with more chocolate chips, if desired.
Bake for 60 to 90 minutes, depending on your oven. The pumpkin bread is done when the top is set and you can insert a toothpick in the middle of the cake without any wet batter sticking to it (a few moist crumbs are fine).
Remove the pan from the oven and allow the bread to cool completely before plating, slicing, and serving.