MIX dressing and Miracle Whip; pour over chicken in glass bowl. Stir to evenly coat chicken. Refrigerate 20 min. to marinate.
HEAT barbecue to medium-high heat. Remove chicken from marinade; discard marinade. Thread chicken and onions alternately onto 16 skewers.
GRILL 8 to 10 min. or until chicken is done, turning occasionally. Meanwhile, place lemon, cut-sides down, on barbecue grate next to kabobs.
SQUEEZE lemon juice over kabobs just before serving.