These are perfect to serve with any roasted or grilled fish or meat. They can be made in advance, stuffed, stored in the fridge, and ready to bake when needed.
Preheat oven to 350 degrees F.
Wash potatoes and pat dry. Pierce with a fork several times, and bake until fork tender, about 45 minutes to 1 hour, depending on size of potato. Cool until warm to the touch. Slice in half lengthwise.
Scoop contents of potatoes into a medium sized bowl. Mash potatoes with a masher, ricer or food mill. Add the sour cream, cheddar cheese, pancetta and chives. Stir with wooden spoon or spatula to combine. Fill skins with potato mixture, mounding slightly. Place the potatoes on a baking sheet lined with parchment or foil. Bake until golden brown and heated through, about 25 to 30 minutes.