In a small skillet, saute onion in butter until tender. In a 5-qt. slow cooker, combine the onion, milk, soups, corn, Creole seasoning and garlic powder.
Cover and cook on low for 3 hours. Stir in shrimp and cream cheese. Cook 30 minutes longer or until shrimp are heated through and cheese is melted. Stir to blend. If desired, garnish with minced chives.