Combine first 3 ingredients in a large heavy-duty, zip-top plastic bag; add chicken. Seal bag, and shake gently to coat chicken. Marinate in refrigerator 30 minutes to 8 hours.
Remove chicken from marinade, reserving marinade. Alternately thread chicken and onions onto 4 (12-inch) metal skewers. Brush kabobs with reserved marinade.
Place chicken on rack of a broiler pan coated with cooking spray. Broil 5 1/2 inches from heat (with electric oven door partially opened) 5 minutes on each side or until chicken is done.