Heat 10-inch skillet over medium-high heat. Add 2 tablespoons vegetable oil, swirling to coat. Sprinkle 4 to 6 boneless skinless chicken breasts on both sides with salt and pepper. Cook in oil 10 to 12 minutes, turning once, until juice of chicken is clear when center of thickest part is cut (at least 165°F). Remove from skillet; cover with foil to keep warm.