Stir together ½ cup Kikkoman Teriyaki Baste & Glaze, reserved pineapple juice and mustard, equally divide into 2 resealable bags, add chicken to one and vegetables into the other and toss.
Remove chicken and vegetables from bags, discard marinade. Alternately thread chicken, pineapple chunks, bell peppers and mushrooms onto skewers.
Grill or broil 10 minutes turning and brushing occasionally with remaining ¼ cup Kikkoman Teriyaki Baste & Glaze or until chicken is no longer pink. Discard any remaining glaze.
