Spray a casserole dish (9x13-inch or equivalent). Preheat oven to 350 degrees F.
Layer the corn, green beans, water chestnuts, and onion in the casserole dish.
12 ounce can whole corn, 12 ounce can French-style green beans, 6 ounce can water chestnuts, 1/2 cup sweet yellow onion
Mix together the sour cream and soup and pour over the vegetables.
1/2 cup sour cream, 12 ounce can cream of celery or mushroom soup
Sprinkle cheese and garlic powder over the soup mixture.
1 cup shredded Cheddar cheese, 1/2 teaspoon garlic powder
Sprinkle the crumbled crackers on top.
15 Ritz crackers
Pour the melted butter over the crackers.
6 tablespoons melted butter
Bake for 30-40 minutes until golden and bubbly.
Enjoy.