Heat grill to medium heat. Cut 4 sheets of heavy-duty foil, 18×12 inches, and spray them with cooking spray.
Place a chicken breast on each piece of foil. Spoon a tablespoon of ranch dressing over each piece of chicken.
Mix ¼ cup additional dressing with ¼ cup water and mix with veggies. Spoon veggies evenly over chicken.
Bring up the foil and seal edges. Grill foil pouches about 20 minutes; turn and cook another 15 minutes or until veggies are tender and juice of chicken is clear when center of thickest part is cut and internal temperature reaches 170 F when tested with a meat thermometer. To serve, carefully open packs and sprinkle with Parmesan or your family’s favorite shredded cheese.