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.