MIX barbecue sauce, crushed pineapple with juice and garlic until well blended; set aside. Place chicken in large glass dish or resealable plastic bag. Pour barbecue sauce mixture over chicken; cover. Refrigerate at least 1 hour to marinate. Drain; discard marinade.
THREAD chicken onto 8 skewers alternately with pineapple chunks, pepper, onion and zucchini.
GRILL 12 to 15 min. or until chicken is cooked through, turning after 6 min.