Cover the chicken with plastic wrap or place in a large resealable bag. Pound the chicken to an even thickness with a meat mallet or the bottom of a heavy skillet. Sprinkle the chicken liberally with salt and pepper.
Heat a medium skillet with a lid over medium-high heat. Add the oil and swirl to coat the skillet. Place the chicken in the skillet and cook for 1 minute without moving. Flip and cook for another minute. Add the chicken stock, cover with the lid and transfer to the oven. Cook, covered, for 8 minutes.
Set the skillet on the stovetop (no heat) with the lid still on; let sit for 8 minutes more, without lifting the lid. After 8 minutes, the chicken should be at 165 degrees F. Slice and serve.