Cook chicken in large skillet sprayed with cooking spray on medium-high heat 2 min. on each side or until browned on both sides. Move chicken to edge of skillet.
Add vegetables, Macaroni, Cheese Sauce
Mix, water and 1/2 cup cheddar to center of skillet; stir. Bring to boil; cover. Simmer on medium-low heat 12 min. or until chicken is done (165F), stirring macaroni mixture occasionally.
Remove from heat.
Remove chicken from skillet. Stir macaroni mixture; spread to evenly cover bottom of skillet. Top with chicken and remaining cheddar; cover.