HEAT oil in large skillet on medium-high heat. Add chicken and onions; cover with lid. Cook 5 to 7 min. on each side or until chicken is done (170ºF). Remove chicken from skillet; cover to keep warm.
ADD tomatoes, dressing and lemons to onions in skillet; cook 4 min. or until heated through, stirring frequently.
RETURN chicken to skillet. Spoon sauce over chicken. Cook 1 min. or until chicken is heated through; top with cheese.
