Hash Brown Chicken Casserole

0 Preheat oven to 375 degrees.
1 Break up any clumps of hash brown potatoes. Add hash browns, onion, chicken, and shredded cheese to a large mixing bowl.
2 Mix well.
3 In a small bowl, combine the sour cream, condensed soup, and ranch dressing mix.
4 Whisk until smooth.
5 Pour this mixture over the potato mixture and fold in until everything is covered in sauce.
6 Spoon potato mixture into a 9x13x2 inch baking dish that's been sprayed with no-stick cooking spray.
7 Bake for 45 minutes.
8 In a small bowl, combine the crushed Corn Flakes with the melted butter.
9 Toss to coat.
10 Spread the cornflake mixture over the top of the casserole and bake for 10 to 15 more minutes or until golden brown and bubbly around the edges.
11 Sprinkle with green onions before serving.