Preheat oven to 350 degrees F. Coat a 24-cup mini muffin tin with cooking spray.
Pulse oats in a blender until finely ground. Add baking powder, baking soda and salt; pulse once or twice to blend. Add eggs, banana, brown sugar, oil and vanilla; puree until smooth. Stir in chocolate chips. Fill the prepared muffin cups.
Bake until a toothpick inserted in the center comes out clean, 15 to 17 minutes. Cool in the pan on a wire rack for 5 minutes, then turn out to cool completely.
