HEAT oven to 350°F.
BRING water and 1 Tbsp. dressing to boil in large skillet on medium-high heat. Stir in spinach, stuffing mix and peppers; cover. Remove from heat. Let stand 5 min.
PLACE chicken, top sides down, on cutting board; spread with stuffing mixture. Roll up, starting at one short end of each breast. Place, seam sides down, in 8-inch square baking dish; brush with remaining dressing.
BAKE 35 min. or until chicken is done (165ºF). Top with cheese; bake 5 min. or until melted.