Preheat oven to 375 degrees. Spray an 11 x 7 baking pan with non-stick cooking spray.
In a large mixing bowl place paper towels inside. Pour bag of thawed shredded hashbrowns into bowl on top of paper towels. Squeeze any excess water from hashbrowns. Remove paper towels and toss.
To the hashbrowns add melted butter, salt, black pepper, garlic powder, minced onion, cream of soup, sour cream and half of the shredded cheese. Mix well to combine.
Spread mixture into prepared pan evenly. Sprinkle with remaining shredded cheese. Cover with foil tightly. NOTE: if you are using regular foil, spray the bottom side of foil before covering pan. This will prevent the cheese from sticking to pan.
Place prepared pan into preheated oven for 35 minutes. Remove foil. Place oven temperature to 400 degrees. Place pan back in oven uncovered for 5-10 minutes until cheese is golden brown. Let casserole sit for 5-10 minutes before serving. Sprinkle with chives as a garnish if desired.