In a large bowl, combine the thawed hash browns, chopped onion, salt, pepper, and garlic powder.
Heat a large nonstick skillet over medium heat and melt the butter.
Place half of the hash brown mixture into the skillet, pressing down to form a large patty.
Cook for 5-7 minutes, or until the bottom turns golden brown and crispy.
Sprinkle the cheddar cheese and crumbled bacon over the cooked side of the hash brown patty.
Carefully place the remaining hash brown mixture on top of the cheese and bacon, pressing down gently.
Cook for another 5-7 minutes, then carefully flip the entire hash brown to cook the other side until golden brown, about 5 minutes.
Transfer the stuffed hash brown to a cutting board, cut into wedges, and serve with a dollop of sour cream and a sprinkle of chives.