Meanwhile, cook and stir chicken in large nonstick skillet 3 to 4 min. or until no longer pink. Remove from skillet; cover to keep warm. Add onions and dressing to skillet; cook 5 min. or until onions are crisp-tender, stirring frequently. Return chicken to skillet. Stir in broth. Bring to boil; simmer on medium-low heat 3 min. or until chicken is done, stirring occasionally.