Preheat oven to 375°F (190°C). Grease a large baking dish.
Season pork chops with salt, pepper, garlic powder, and paprika.
(Optional) Sear pork chops in butter for 2–3 minutes per side until lightly golden.
Layer half of the sliced potatoes in the baking dish. Season lightly.
Place pork chops over potatoes, then add sliced onions.
Top with remaining potatoes.
In a bowl, whisk soup and milk until smooth. Pour evenly over casserole.
Cover tightly with foil and bake 60 minutes.
Remove foil and bake an additional 15–20 minutes until golden and bubbling.
Rest 10 minutes before serving.