Heat oven to 400°F (200°C). Scrub and prick the potatoes, then bake directly on the rack until tender, 50 to 60 minutes.

Let potatoes cool slightly. Halve lengthwise and scoop most flesh into a bowl, leaving a thin layer. Chop 2 or 3 of the skins into rough pieces, toss with oil and salt, and bake on a sheet at 400°F for 12 to 15 minutes until crisp.

While skins crisp, cook bacon in a skillet over medium heat until crunchy, about 8 to 10 minutes. Drain and crumble.

Whisk together sour cream, mayonnaise, garlic powder, salt, and pepper.

Break potato flesh into chunky pieces with a fork. Fold in crispy skins, most of the bacon, cheddar, and green onions, then the dressing. Top with remaining bacon, cheese, and green onions. Serve warm or at room temperature.