Preheat oven to 375.
Melt the butter in a small skillet over medium heat. Add the onions, celery, and sausage and sauté until softened, about 5 minutes.
Cut the chicken into bite-sized pieces and pat it dry. Place on the bottom of a lightly greased 9 x 13-inch baking dish. Sprinkle lightly with salt and pepper.
Combine the cream of chicken soup, sour cream, milk, ½ tsp dried thyme, and ¼ tsp ground sage. Add it to the top of the chicken and spread evenly to coat.
Add the thawed green beans next. Note: The green beans will be al dente (have a slight crunch). For softer green beans, submerge them into the sauce a bit.
Combine the stuffing mix, chicken broth, sauteed onions, celery, and diced sausage. Add it to the top of the casserole dish.
Cover and bake for 40 minutes. Remove the cover and bake for 5 more minutes.
Serve with my mashed potatoes and 10-minute chicken gravy!