Preheat oven to 375 degrees. Line a rimmed baking sheet with foil and lightly spray with cooking spray (like PAM).

Place corn tortillas on a microwave safe plate (they can be stacked, but make sure you have pulled them apart a bit). Microwave about 30 seconds (you may have to rewarm bottom tortillas) so they are easier to roll and work with. Place a little chicken, cheese, and a drizzle of ranch towards one edge of the tortilla. Gently roll the tortilla around the filling tucking as you go to get a tight roll. Place seam side down on the baking sheet. Bake 15-18 minutes or until tortillas begin to harden and filling is hot and cheese melted. Serve with a side of ranch.