In a large skillet melt 1/2 cup butter over medium heat. Add 1 can cream of chicken soup and the whipped cream cheese with chives. Stir until well blended.
Add in 1 cup cubed mild cheddar and 1/4 cup of milk. Continue stirring until cheese is melted and mixture is creamy.
Place bag of thawed hash browns into a large bowl. Add cheese sauce mixture. Stir together.
Pour cheesy hash browns into a sprayed 2 quart baking dish or casserole slow cooker.
Top with 1 cup of grated mild cheddar cheese.
If doing the 2 quart baking dish, bake in a 350° F oven for 1 hour until fork tender.
If making in a casserole crock pot bake on low for 3.5 hours or on high for 2 hours.