Preheat the oven to 350°F and line a muffin tray with muffin liners.
In a large bowl, whisk together the white sugar, brown sugar, and softened butter until well combined.
Add the eggs one at a time, mixing well after each addition.
Add the pumpkin puree and mashed bananas and stir briefly to combine.
Add the pumpkin pie spice, vanilla, baking powder, and baking soda. Mix well.
Add 1 cup of flour and mix until incorporated.
Add the remaining ¾ cup flour and mini chocolate chips. Mix just until combined. Do not overmix.
Scoop the batter evenly into the prepared muffin liners.
Bake at 350°F for 18–20 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
Transfer the muffins to a cooling rack and let them cool for a few minutes before serving.