Heat oven to 350°F. Spray 1 1/2-quart casserole with cooking spray.
Mix refried beans and 2 tablespoons taco seasoning mix in small bowl; spread in bottom of casserole. In medium bowl, mix cream cheese, celery, dressing and hot sauce. Stir in chicken. Spoon chicken mixture over refried beans in casserole.
Bake uncovered 35 minutes or until heated through. Let stand 10 minutes before serving. Serve with tortilla chips, celery sticks or other veggies or crackers.