Preheat the oven to 350 degrees F. Spray a 13x9 casserole dish with cooking spray and set aside.
In a large pot of boiling water, add green beans and cook for 3 minutes, until bright green. Drain, then place in an ice bath to cool. Transfer to a large bowl and set aside.
Meanwhile, in a saucepan set over medium heat, whisk together the cream of chicken soup, milk, Worcestershire sauce, garlic powder, and pepper. Bring the mixture to a simmer, then whisk in 1 cup of the cheese until completely incorporated. Pour over the green beans and toss to coat, then transfer to a casserole dish.
Top with remaining cheese, then bake for 20 minutes, until warmed through and bubbling around the edges.
Top the casserole with fried onions and the crumbled bacon and bake for an additional 5 minutes.