Preheat the oven to 180°C (356°F).
In a bowl, mix together the protein powder, oat flour, cocoa powder, baking powder, and salt.
In another bowl, mash and mix the banana, egg, milk, and honey together.
Combine the dry and wet ingredients, mixing until well incorporated.
Gently fold in the chocolate chips.
Divide the batter evenly into muffin molds.
Bake for 20-25 minutes at 180°C (356°F).