In a blender or food processor, add the rolled oats, mashed banana, milk, egg, maple syrup, vanilla extract, baking powder, cinnamon, and salt. Blend until smooth and creamy, about 30 seconds. Stir in the chocolate chips by hand.
Spray 2 oven-safe ramekins (about 8 oz each) generously with cooking spray. Divide the batter evenly between them.
Preheat the air fryer to 325°F.
Place the ramekins in the air fryer basket. Air fry for 15 to 18 minutes until the tops are golden brown, set, and slightly puffed. A toothpick inserted in the center should come out clean or with just a few moist crumbs.
Carefully remove the ramekins from the air fryer and let them cool for 3 to 5 minutes. The baked oats will settle slightly as they cool.
Enjoy straight from the ramekin topped with fresh berries, a drizzle of nut butter, or an extra splash of maple syrup.