Toss chicken breast with ginger and corn starch. Heat oil in large skillet or wok over high heat. Add chicken; stir-fry for 3 to 4 minutes until chicken is no longer pink. Add mushrooms, snow peas and bell pepper; stir-fry 2 to 3 minutes until vegetables are crisp and tender. Add onions and sauce mix. Bring to a boil, stirring constantly, and boil for 1 minute.