Preheat oven to 425 degrees F (220 degrees C). Grease a 2-quart (1.9 L) baking dish; set aside. In a large bowl, whisk together soup and milk until smooth. Stir in cheese, chives, and cooked elbow pasta to combine. Transfer mixture to prepared baking dish. In a small bowl, combine bread crumbs and melted butter; sprinkle over pasta. Bake for 15 to 20 minutes or until hot and bubbling.