Preheat your oven to 350°F. Lightly coat a 1.5 to 2-quart baking dish with nonstick spray and set it aside.
In a large mixing bowl, blend the cream of mushroom soup, milk, Worcestershire sauce, garlic powder, salt, and black pepper until well combined.
Fold in the green beans and half of the crispy fried onions, stirring until evenly incorporated.
Pour the green bean mixture into the prepared baking dish. Bake uncovered for 25-30 minutes, or until the center of the casserole is bubbling.
Carefully remove from the oven, sprinkle the remaining crispy onions on top, and return to the oven for an additional 5-10 minutes, or until the onions are golden and crisp.
Allow the casserole to rest for 5 minutes before serving.