Preheat oven to 450°F.
Scrub potatoes, pat dry, and prick all over with a fork.
Bake potatoes directly on rack for 50-60 minutes until tender.
Let potatoes cool 5-10 minutes, then halve lengthwise.
Scoop out flesh, leaving a 1/4-inch border attached to skin.
Whisk oil, Parmesan, salt, garlic powder, paprika, and pepper.
Brush oil mixture inside and outside each skin.
Bake skins 10 minutes, turning halfway, until golden and firm.
Sprinkle Cheddar and bacon evenly over skins.
Bake 2 minutes until cheese melts and bubbles.
Transfer to platter, top with sour cream and green onions.
Serve immediately while warm and crisp.