Combine flour, baking powder, baking soda, and salt in a large bowl. Set bowl aside. In a separate bowl, whisk together the skim milk, melted butter, eggs, sugar, and vanilla. Make a well in the center of the dry ingredients and stir in the wet ingredients, being careful not to over mix the batter. Gently fold in the banana, chocolate chips, and nuts.
Heat a large skillet over medium heat, and coat with cooking spray. Pour 1/4 cupfuls of batter onto the skillet, and cook until bubbles appear on the surface. Flip with a spatula, and cook until browned on the other side.