Boil the potatoes in lightly salted water in a medium saucepan over medium heat until fork-tender, about 12 minutes. Drain and dry the potatoes completely.
Preheat the oven to 475 degrees F.
Place the potatoes on a baking sheet. Brush a potato masher with olive oil, then gently press down to smash a potato. Rotate the masher ninety degrees and press down again to create a crisscross pattern on top of the potato. (The top of the potato should have jagged edges.) Repeat with the remaining potatoes. Brush the tops of the potatoes with the remaining oil. Sprinkle with a generous pinch of salt and the pepper. Bake until golden brown and crisp, about 15 minutes.
Meanwhile, cook the bacon in a skillet over medium heat, flipping as needed, until crisp, about 12 minutes. Set aside.
Remove the potatoes from the oven and immediately sprinkle the cheese on each, letting it melt slightly. Transfer the potatoes to a platter and top with a touch of sour cream. Crumble the bacon and distribute over the potatoes. Sprinkle over the chives and serve.