If you don't have leftover chicken on hand, pick up a rotisserie one at the market, or bake a couple of pieces of chicken at 350 degrees until cooked through. Feel free to substitute beef, pork, or turkey in place of the chicken. Alternatively, make these vegetarian, using equal parts black beans and chopped, cooked vegetables. Make a double batch and freeze the extras to use for future suppers or school lunches. Reheat in the oven or toaster oven.