Cream Cheese Corn Casserole with Green Chiles



3 cans of corn, drained
8 ounces cream cheese
4 ounces canned green chiles, chopped
1/2 small yellow onion, chopped very fine
1/2 tsp garlic powder
1/2 tsp old bay or cajun/creole seasoning
1/4 tsp salt
1/8 tsp pepper
1 tsp white sugar
1/2 cup shredded cheddar or colby jack cheese
additional shredded cheese for sprinkling