Boil chicken until cooked through (no longer pink inside), about 20-30 minutes. Cut into bite size pieces and place in a 9x13 inch baking dish that has been sprayed with non-stick cooking spray.
Combine soup, sour cream, vegetables of your choice. Pour mixture over chicken
In a separate bowl, combine crushed cornflakes and melted butter and sprinkle over the top of the chicken mixture.
Cover and bake for 30 minutes (or freeze for baking at another time).