Cook bacon in a medium skillet over medium-high until crisp. Drain on paper towels, reserving drippings in skillet. Crumble bacon. Cook scallions in hot drippings until lightly browned and crispy, 3 to 4 minutes. Transfer to paper towels to drain. Top warm potatoes with scallions and bacon.
Make it ahead: Prepare 1 day ahead; cover and refrigerate. Reheat before serving.