Pour oats in a medium skillet and set over medium heat. Toast oats 3-5 minutes, stirring frequently, until oats are a light golden brown and fragrant. Allow to cool slightly.
In a large bowl, whisk mashed bananas, melted butter, sugar, vanilla, egg, and buttermilk until smooth. In a separate medium bowl, combine flour, toasted oats, baking powder, baking soda, and salt.
Fold flour mixture into liquid until batter is just combined. Fold in chocolate chips.
Preheat a large skillet or griddle over medium heat and lightly brush with butter. Working in batches, drop pancake batter by heaping 1/3 cupfuls onto hot skillet and allow to cook 2-3 minutes on each side until pancakes are golden brown. Repeat cooking method with remaining batter, adding more butter to skillet as needed.
Serve pancakes warm with banana slices, chocolate chips, and maple syrup on top. Enjoy!