Make AheadPrepare dip as directed except do not top with remaining cheese sauce and sour cream; spoon into airtight container. Refrigerate up to 24 hours. Remove from refrigerator 30 min. before serving. Stir dip; spoon into microwaveable dish. Microwave on HIGH 5 min. or until heated through, stirring after 3 min. Drizzle with remaining cheese sauce; top with sour cream.