Preheat the oven to 350 degrees F (175 degrees C). Line a baking sheet with aluminum foil; spray foil with cooking spray.

Arrange chicken thighs, skin-side up, on the prepared baking sheet.

Combine garlic salt, onion salt, oregano, thyme, paprika, and pepper in a small bowl; mix until well combined.

Sprinkle spice mixture liberally over chicken thighs.

Bake chicken in the preheated oven until skin is crispy, thighs are no longer pink at the bone, and the juices run clear, about 1 hour. An instant-read thermometer inserted near the bone should read 165 degrees F (74 degrees C).

Serve hot and enjoy!