Preheat the oven to 350 degrees F.
Wash potatoes then use a fork and poke holes about 1/2" deep into the skins of the potato. Rub cooking oil on the outsides of the potatoes, then place in a 9" x 13" baking dish. Season with salt on all sides.
Bake in a preheated oven for 50-60 minutes, or until fork tender.
Remove from the oven and allow the potatoes to cool for about 5-10 minutes until you can handle them.
Once cooled down, scoop out the inside of the potato. Leave a small layer of potato on the skins so the potato skins keep their shape. Put the insides of the potato in a medium sized mixing bowl.
Melt the remaining 2 tablespoons of butter and brush the inside of each potato skin with the melted butter. Sprinkle with garlic salt, then set aside.
Mash the potatoes until mostly smooth, then add the sour cream, shredded cheeses, garlic salt, onion powder, salt, and pepper. Taste test and add more seasonings if needed.
Spoon the potato mixture into the potato skins. Sprinkle with the remaining shredded cheddar cheese, top with bacon bits, and cover with foil.
Bake again for 30 minutes before removing the foil and baking for an additional 10 minutes, or until the bacon is crisp and the cheese is melted.
Remove from oven and sprinkle with sliced green onions before serving warm. Enjoy!