Pour 1/4 cup Wish-Bone Italian Dressing over chicken in large, shallow non-aluminum baking dish or plastic bag. Cover, or close bag, and marinate in refrigerator, turning occasionally, 30 minutes to 3 hours.
Meanwhile, combine tomatoes, onion, basil and 1/4 cup dressing in medium bowl. Cover and marinate in refrigerator for at least 30 minutes.
Remove chicken from marinade, discarding marinade. Grill or broil chicken, turning once and brushing frequently with remaining 1/4 cup dressing, 12 minutes or until chicken is thoroughly cooked. Serve tomato bruschetta over chicken.