Preheat oven to 400F.
Rub potatoes with oil and cook until fork tender, roughly 50 minutes.
In a large bowl, combine butter, bacon, sour cream, cream cheese, milk, kosher salt, black pepper, and garlic powder. Mix until well-combined.
Remove potatoes from the oven and allow them to cool for 10-15 minutes. Reduce oven temperature to 325F.
Cut warm potatoes lengthwise and carefully scoop out the interior into the bowl with the filling mixture. Add half of your cheese. Mix well (I recommend using a potato masher). Add more salt, pepper, and garlic powder to taste.
Spoon potato mixture back into the potato skins, top with the remaining cheese, and bake for approximately 15 additional minutes. Potatoes should be warmed all the way through and the cheese should be melted. I like to broil mine for 1 minute before taking them out of the oven.
Top with green onions.