Cook 4 chicken breasts in saucepan until tender on medium heat, approximately 15 minutes. Cool and cut into small pieces. Set aside.
Prepare 1 box Stove Top stuffing according to package and press into bottom and sides of casserole dish. Mix can of soup, milk and cut-up chicken, mushrooms, and green beans. Put it in the casserole dish over the stuffing nest. Put in oven covered at 350 degrees for 30 minutes.