Cover chicken with plastic wrap and pound with a rolling pin, meat mallet or heavy skillet until flattened to an even thickness, about 1/2 inch. Combine flour, salt and pepper in a shallow dish; dredge the chicken (discard any leftover flour).
Heat oil in a large nonstick skillet over medium-high heat. Cook the chicken until well browned and no longer pink in the center, 4 to 5 minutes per side. Serve.