Boil chicken in pot until chicken is no longer pick. Remove from heat, let cool in water. When cooled completely, remove from water, reserve water.
Bring water back to a boil and add egg noodles. Cook until almost done.
Pull chicken apart into small shredded like pieces.
Chop green onions into very small pieces, also chop mushrooms into small pieces.
In a bowl, combine soups, 1 cup cheese, vegetables and garlic powder.
Place egg noodles and chicken in greased casserole dish. Slowly combine the soup mixture, until noodles and chicken are coated.
Cover and bake 350º for 30 minutes.
Take out and uncover, stir, then add the remaining cheese, bread crumbs and pepper.
Leave uncovered and return to over on 400º for another 15 minutes or until cheese is melted completely.
Let stand 10 minutes before serving.