Melt margarine in large saucepan on medium heat. Add onions; cook and stir 5 min. Stir in mushrooms; cook 10 to 12 min. or until lightly browned, stirring occasionally. Add chicken; cook and stir 5 min. or until done. Stir in cream cheese product and broth; cook 3 min. or until cream cheese is completely melted. Stir in vegetables.