Coat chicken with flour, salt and pepper, then brown in oil. Put into roaster with green pepper strips.
Sauce: Drain pineapple and add enough water to juice to make 1 1/4 cups. In a saucepan, add pineapple juice mixture, sugar, cornstarch, vinegar, soy sauce and chicken cubes=. Boil for 2 minutes. Pour over chicken. Bake, uncovered, at 350F for 30 minutes. Add pineapple and bake for 30 minutes longer.