Preheat the oven to 425°F (218°C). Line a rimmed baking sheet with foil if desired and place a wire rack on top.
If needed, pound the chicken breasts to an even thickness (about 1/2 inch) so they cook evenly.
In a shallow bowl, pour the ranch dressing; in a separate shallow dish, combine the panko, grated Parmesan, garlic powder, seasoned salt, black pepper, and red pepper flakes.
Dip each chicken breast into the ranch to coat completely, letting excess drip off, then press both sides into the panko-Parmesan mixture until well coated.
Place the coated chicken on the prepared wire rack set over the baking sheet. Sprinkle additional Parmesan on top if desired and lightly spray the tops with cooking spray.
Bake for 20–25 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) when checked with a meat thermometer.
Let the chicken rest a few minutes before serving.