Preheat oven to 350 degrees F. Spray a 8"x5" (or similar size) loaf pan with baking spray (the kind with flour in it) and set aside. In a large bowl mash the bananas until completely smooth. Stir in the melted butter until smooth. Add the sugar, egg, vanilla, baking soda, salt and flour and stir until the batter is thick and combined. Fold in the chocolate chips then pour/scoop the batter into the prepared loaf pan. Bake for 50 minute to 1 hour, or until toothpick inserted in center comes out clean. Let cool completely on a wire rack. Slice and enjoy!