Preheat the oven to 350°F (175°C).
In a large mixing bowl, combine the drained diced potatoes and green beans.
Add the condensed cream of chicken soup and mix well until all ingredients are evenly coated.
Stir in the shredded Colby cheese, reserving a handful for topping.
Transfer the mixture into a greased 9x13 inch baking dish.
Sprinkle the reserved cheese over the top.
Bake uncovered for 25-30 minutes until the casserole is heated through and the cheese on top is melted and slightly golden.
Let cool for a few minutes before serving.