Preheat the oven to 350°F then line an 8x8-inch baking dish with parchment paper.
In a large bowl, combine 1 cup pumpkin puree, ¼-⅓ cup pure maple syrup, ½ cup non-dairy milk, ¼ cup tahini, and 1 teaspoon vanilla extract. Whisk vigorously until smooth, with no lumps remaining.
To the bowl, add 1 cup flour, ½ cup protein powder, 1 teaspoon cinnamon, 1 teaspoon pumpkin pie spice, 1 teaspoon baking powder, ½ teaspoon baking soda, and ½ teaspoon salt. Fold together until a batter begins to form. The batter will be thick but that's to be expected. Fold in the chocolate chips until combined.
Transfer the batter to the lined baking dish. Using a rubber spatula, press the batter out and down to spread it across the dish. It doesn't have to be perfect as it will spread some during baking. Top with 1-2 tablespoons chocolate chips then bake in the oven for about 25 minutes, until golden and firm in the center. Allow to cool for at least 20 minutes before using the parchment paper to lift out of the baking dish.
Slice into 9 or 12 squares then serve and enjoy! Leftovers can be stored in an airtight container for up to 1 week.