Preheat the oven to 400 degrees F. Line a baking sheet with aluminium foil and set aside.
Wash potatoes with a stiff brush and cold water, then pat dry. Pierce each potato with a fork about 8-12 times. Place potatoes on the baking sheet and bake for 1 hour.
Let potatoes cool for 10–15 minutes.
Meanwhile, in a small bowl, combine oil, Parmesan, salt, pepper, garlic powder and paprika. Mix well.
Cut potatoes in half. Spoon out most of the insides and place in a large bowl, reserving potato skins.
Brush oil-Parmesan mixture over the tops and bottoms of each potato skin.
Lightly mash potato insides and mix in sour cream (you can use more or less to your liking), about 1 cup cheddar, bacon pieces, and more salt and pepper to taste. Mix well.
Spoon mixture back into potato skins and discard any excess skins. Sprinkle potatoes with remaining 1 cup cheddar.
Place back on the baking sheet and bake for 16–18 more minutes. Sprinkle with chives before serving.