Heat gas or charcoal grill. Place 1/4 cup of the cooking sauce in small bowl to use for brushing. Reserve remaining cooking sauce in microwavable bowl to serve with skewers.
On each of 4 (10- to 12-inch) metal skewers, alternately thread chicken, zucchini, onion and tomatoes. Brush with oil.
Place skewers on grill over medium heat. Cover grill; cook 10 to 15 minutes, turning skewers 2 or 3 times and brushing with 1/4 cup cooking sauce from small bowl during last 5 to 8 minutes of grilling, until chicken is no longer pink in center.
Microwave cooking sauce that is in microwavable bowl uncovered on High 20 to 30 seconds or until hot. Serve with skewers.