place chicken breast into a small casserole dish. Mix the olive oil, apple cider vinegar and italian seasoning together stirring well. Pour the seasoning mixture over the chicken breast covering completely.
cover casserole dish with plastic wrap and place in refrigerator to marinate. After about 30 minutes turn the chicken breast. with a spoon make sure the seasoning mixture is covering the chicken breast by scrapping the bottom of the dish and spreading any dripped mixture back on the chicken. Cover back up with wrap and let marinate another 30 minutes.
After chicken has marinated for about an hour, take out of refrigerator and you are ready to grill. Place chicken on hot grill around 350 degrees, and grill on each side for about 10 minutes, or until center of chicken breast is white and no longer pink.