Prepare the green beans by draining canned beans or blanching fresh/frozen beans in boiling water for 3-5 minutes, then drain and rinse.
In a large mixing bowl, combine cream of mushroom soup and sour cream, then add garlic powder, onion powder, salt, and pepper. Mix until smooth.
Gently fold the drained green beans into the creamy sauce, then add ½ cup of shredded cheddar cheese and ½ cup of French fried onions. Mix until well combined.
Transfer the mixture to a greased 9x13-inch baking dish, spread evenly, and top with remaining cheddar cheese and French fried onions.
Preheat oven to 350°F and bake for 25-30 minutes until bubbly and golden brown. Let cool for 5 minutes before serving.