PREPARE stuffing mix as directed on package.
MEANWHILE, cook chicken in large nonstick skillet sprayed with cooking spray on medium-high heat 2 to 3 min. or until chicken is lightly browned. Stir in milk, cream cheese spread and vegetables; bring to boil. Cook on medium-low heat 5 min. or until cream cheese is completely melted, stirring constantly.
TOP with shredded cheese and stuffing; cover. Cook 5 min. or until chicken is done (165ºF).