1Heat oven to 400°F. Grease 2-quart casserole with shortening or cooking spray. In 10-inch skillet, cook sausage, carrots, celery and onion over medium heat, stirring occasionally, until sausage is browned and vegetables are tender; drain. Stir in chicken, soup and 1/2 cup milk.
2Place flour in large bowl. With pastry blender or fork, cut in butter until mixture looks like coarse crumbs. Add 2/3 cup milk; stir until dough leaves side of bowl. Press half of dough into bottom of casserole. Pour sausage mixture over dough. Drop remaining dough by tablespoonfuls over sausage mixture.
3Bake 25 to 30 minutes or until sausage mixture is hot and bubbly and biscuits are golden brown.