Preheat the oven to 375 degrees F (190 degrees C). Grease a 12-cup muffin tin or line cups with paper liners.

Whisk flour, sugar, baking soda, and baking powder together in a bowl. Stir in bananas, mayonnaise, and chocolate chips until well combined. Spoon batter into the prepared muffin cups, filling each about 3/4 full.

Bake in the preheated oven until golden and tops spring back when lightly pressed, about 20 minutes.