Combine first 5 ingredients in a medium bowl, and stir with a whisk. Set aside.
. Sprinkle chicken evenly with breadcrumbs. Heat oil in a large nonstick skillet coated with cooking spray over medium-high heat. Add chicken, and cook 2 to 3 minutes on each side or until lightly browned. Add mushrooms and reserved broth mixture; cover, reduce heat, and simmer 7 to 8 minutes or until chicken is done. Sprinkle with green onions.