Preheat the air fryer to 320°F (160°C).
Combine rolled oats, banana, milk, maple syrup, baking powder, vanilla, and salt in a high-speed blender.
Blend on high for 30 seconds or until the batter is completely smooth and liquid.
Lightly grease an 8-ounce or 10-ounce oven-safe ramekin with non-stick cooking spray.
Pour the blended batter into the prepared ramekin.
Sprinkle dark chocolate chips over the top of the batter.
Place the ramekin into the air fryer basket and cook for 10 to 12 minutes, or until the center is set and a toothpick comes out clean.
Remove the ramekin carefully and allow to cool for 2 minutes before serving.