Preheat oven to 350°. Melt butter in a large skillet over medium heat. Add celery, onion, peppers and mushrooms. Cook, stirring frequently, until onions are tender (about 15 minutes).
While vegetables are cooking, butter a 1-quart casserole; set aside. When vegetables are tender, stir in soup, broth, Garden Medley Dip Mix, chicken and peas.
Pour mixture into prepared pan and bake, covered, for 30 minutes. Uncover and sprinkle with cashews and noodles and bake 10 to 15 minutes more. Serve over rice. Makes about 9 cups or 6 servings.