Heat oven to 375°F. In 2-quart saucepan, heat vegetables, chicken and gravy to boiling, stirring frequently.
In medium bowl, stir remaining ingredients until well blended. In ungreased 2-quart casserole, spread chicken mixture. Pour batter over chicken mixture.
Bake uncovered 35 to 40 minutes or until crust is golden brown. Let stand 5 minutes before serving.