Make sure chicken is fully thawed and thinly sliced. Preheat oven to 350F. Cover cookie sheet  with aluminum foil. Pour ranch into large bowl. In another bowl, pour cornflakes. Crunch the cornflakes up with your hands (not too small). Mix shredded cheese in with cornflakes. Dip chicken into ranch dressing and cover both sides. Place ranch covered chicken onto cookie sheet fitting tightly with next piece until cookie sheet is full. Completely cover top of chicken pieces with handfulls of cornflake & cheese mix. Slightly press into chicken. Bake approximately 40+minutes or until chicken is thoroughly cooked. Serve with sides of vegetables and/or potatoes. Enjoy!