Heat the grill. Coat four (12-inch) squares of heavy-duty foil with cooking spray. Arrange the potatoes in the center of the foil and drizzle with the olive oil; sprinkle with the seasoning salt and garlic powder. Top with the cheese and bacon; wrap the foil around the potatoes. Grill, covered, over medium heat or coals for 30 to 35 minutes or until the potatoes are tender. Carefully open the foil packets; sprinkle with the green onions and serve topped with the sour cream.