Preheat your oven to 350°F.
In a large mixing bowl, stir together the cream of mushroom soup, milk, soy sauce, black pepper, and garlic powder until smooth and well combined.
Add the drained green beans and 1 1/3 cups of the French fried onions to the soup mixture and stir until the beans are evenly coated.
Pour the mixture into a 9x13-inch baking dish and spread it out evenly.
Bake uncovered for 25 minutes until the casserole is hot and bubbly.
Remove from oven and sprinkle the remaining 1 1/3 cups French fried onions evenly over the top.
Return to oven and bake for an additional 5 minutes until the onions are golden brown.
Let cool for 5 minutes before serving.