In a large bowl, stir together frozen hash browns (or thawed), cheddar cheese condensed soup, sour cream, onion powder and salt and pepper to taste (1/4 to 1/2 tsp. salt). Spread the hash brown mixture over the veggies. Sprinkle with shredded cheddar, cover with foil and bake until completely warmed through, about 55-60 minutes if potatoes are frozen and less (around 35-40 minutes) if they're thawed. Remove the foil and return it to the oven for a few minutes so the cheese can fully melt on top. Serve and enjoy!