Poor ranch dressing into a medium or large sized bowl, and set aside.
In a separate bowl, combine Parmesan cheese, Cheddar cheese, and the packet of ranch dressing mix.
Mix until well combined.
Dip thawed chicken breasts into the bowl of ranch and place on the covered cookie sheet.
Sprinkle the tops of the chicken breast with the cheese and ranch seasoning mixture, until you can't see the chicken breast.
Place the ranch and cheese covered chicken breasts into the hot oven and bake for 30 minutes or until the chicken is cooked all the way through.
Sprinkle with extra Cheddar and Parmesan cheese when it is freshly out of the oven (our family really likes cheese)
Notes
This recipe will work great with boneless chicken thighs, I just normally have boneless chicken breasts on hand! Just follow the ranch chicken recipe as is, but adjust the timing for the chicken as needed since the thickness of the chicken can change the cook time slightly.