Preheat the oven to 375°F and spray a 9 x 13 baking dish with cooking spray.
Place the chicken in a large plastic zip bag. Sprinkle the ranch seasoning over the chicken, zip the bag shut, and gently shake the bag to coat the chicken. Massage the chicken if necessary to ensure the ranch seasoning is evenly dispersed
Open the bag, and use tongs to remove the chicken and place it in the baking dish.
Bake for 30 minutes or until an instant read thermometer reads 165 degrees when inserted in the thickest part of the chicken. Remove the chicken from the oven and transfer to a plate to rest for 5 to 10 minutes before cutting.
Notes
The calories listed are an approximation based on the ingredients and a serving size of 6 ounces of chicken. Actual calories will vary. Any leftover oven baked ranch chicken can be stored in your fridge, in a sealed container, for up to 3 days.