Preheat the oven to 325 degrees F (165 degrees C).
Heat the undiluted cream of mushroom soup in a saucepan over medium heat. Stir in the processed cheese and bacon, and continue stirring until completely melted. Remove from the heat, stir in the mushrooms, then the green beans until evenly coated. Pour the mixture into a casserole dish, and top with the fried onions, leaving a 1 inch margin around the sides.
Bake for 25 to 30 minutes in the preheated oven, until heated through and bubbly. Check near the end of cooking to make sure the onions aren't getting too brown.