Preheat the oven to 400°F with a rack in the center position.Bring a pot of water to a boil over high heat and salt it
Add the potatoes and cook for 5 minutes, or until just fork tender, then drain
Once cool enough to handle, cut the potatoes in half.Meanwhile, heat the olive oil in a large ovenproof skillet or braiser over medium-high heat
Season the chicken all over with the salt.Working in batches, add the chicken, skin side down, to the braiser and cook until the skin is browned, about 4-5 minutes
Flip the chicken and cook until browned, about 3 minutes more
Transfer the chicken to a plate
Add as many potatoes as will fit to the skillet, cut sides down, and cook until lightly browned, 1-2 minutes
Transfer the potatoes to the plate with the chicken
Repeat until all the potatoes are browned.Add the shallots to the skillet and cook, stirring, until lightly browned, 2 to 3 minutes
Stir in the garlic and cook until fragrant, about 1 minute more
Add the chicken stock and bring to a simmer
Add the chicken to the broth, skin sides up
Nestle in the potatoes and top the chicken with the lemon slices
Transfer to the oven and cook until the internal temperature of the chicken reaches 165°F on an instant-read thermometer and the potatoes are tender, about 35 minutes
Transfer the chicken to a plate
Stir in the lemon juice and butter until melted, then taste and season with salt
Return the chicken to the sauce and garnish with pepper and chives
Serve family style over cooked rice or couscous.