Preheat oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish.
In a skillet, heat olive oil over medium heat. Add smoked sausage and cook until lightly browned, about 5–7 minutes. Remove from heat.
In a large bowl, mix cream of chicken soup, sour cream, milk, 1 cup cheddar cheese, garlic powder, paprika, salt, and pepper.
Stir in thawed potatoes, browned sausage, and green onions (if using) until everything is well combined.
Spread mixture evenly into the prepared baking dish.
Top with remaining ½ cup cheese and extra green onions if desired.
Bake uncovered for 40–45 minutes, until hot, bubbly, and golden on top.
Let cool 5–10 minutes, then serve.
