Drain pineapple; reserve 2 tablespoons juice.
Cook; stirring pepper, onion and mushrooms in hot oil, over medium heat, in large skillet, until tender-crisp. Remove vegetables from skillet; set aside.
Cook chicken in same skillet, until chicken is browned. Add vegetables back to skillet with sweet and sour sauce, soy sauce, pineapple chunks and reserved juice. Heat through. Serve over hot cooked rice.