Scrub potatoes well, place in a pan and cover with cold water by at least 1 inch. Add 1 tsp. salt, bring to a boil over medium-high heat and cook until potatoes are tender and a knife can be inserted easily, 15 to 20 minutes. Drain; let cool.
Cook bacon in a skillet over medium heat, turning, until crisp, about 12 minutes. Drain on paper towels. When cool, crumble bacon.
Cut each potato in half crosswise. Trim a small slice from the bottom of each half so it stands upright. With a melon baller or teaspoon, remove center of each potato, leaving a 1/4-inch border. Put potato flesh in a bowl and mash with sour cream; season with salt and pepper. Fold in crumbled bacon. Fill each potato half with sour cream mixture and sprinkle with chives (you may have some filling left over). Serve immediately.