Preheat oven to 400°F. Prepare mega sheet pan with vegetable pan spray.
In large bowl, toss hash browns, sausage, cheddar cheese, 2 tablespoons butter, garlic powder, 1/2 teaspoon salt, and 1/2 teaspoon pepper. Arrange mixture in a single layer on pan. Bake 30 minutes; stirring hallway through.
When hash browns are cooking, brush remaining butter on inside of English muffin slices. Once hash browns have baked for 30 minutes, move all hash browns to one side of pan. On the other side, place English muffin slices butter side up. In hash browns, create 6 wells. Crack eggs into wells, leaving yolk intact. Sprinkle remaining salt and pepper on eggs.
Bake an additional13-15 minutes or until eggs are cooked to desired doneness, rotating pan halfway through. Top with green onions. Serve immediately.