Preheat the oven to 350°F. Line a baking sheet with parchment paper or a silicone baking mat and set aside.
Add pumpkin, sugar, vegetable oil, vanilla, and egg in a large bowl and mix until smooth. In a small dish, combine the baking soda and milk, stirring till the baking soda dissolves. Add this mixture to the other wet ingredients.
In a separate bowl, whisk together the flour, baking powder, cinnamon, pumpkin pie spice, and salt.
Add the flour mixture to the pumpkin mixture and stir until the flour disappears, being careful not to overmix. Gently fold in the chocolate chips.
Drop cookies by rounded spoonful about 2 inches apart on the baking sheet. A 2-tablespoon sized cookie scoop is perfect. (I use one from Norpro.) Bake 10-12 minutes, till the tops are just beginning to show a little browning. You can also test them with a toothpick. When inserted in the center, it should come out clean.
Let cool on the baking sheet for about 5 minutes, then transfer to a cooling rack to cool completely.