Preheat oven to 425°F. Toss fingerling potatoes with 2 tablespoons olive oil, salt, and pepper. Spread on a rimmed baking sheet and roast for 15 minutes.

While potatoes roast, pat chicken breasts dry with paper towels. Season generously with salt and pepper on both sides.

Heat remaining 2 tablespoons olive oil in a large oven-safe skillet over medium-high heat. Once shimmering, add chicken and sear for 4 minutes per side until golden. Transfer to a plate.

Add minced garlic, thyme sprigs, and rosemary sprigs to the skillet. Cook for 30 seconds until fragrant.

Nestle chicken back into the skillet. Squeeze juice from 1 lemon over the chicken and scatter thin slices of the second lemon around it.

Transfer skillet to the oven. Bake for 12 to 15 minutes until the chicken reaches 165°F at the thickest part.

Remove from oven. Stir the roasted potatoes into the skillet or serve alongside the chicken. Drizzle everything with any pan juices and a squeeze of fresh lemon.