Preheat your air fryer to 380°F (193°C) for 5 minutes. After pre-heating, spray with cooking spray, if desired.
Add the chicken thighs to a large zip-top bag or a bowl with a lid. Top with the kosher salt, smoked paprika, garlic powder, oregano, and onion powder. Shake to coat.
Remove from the bag and place the chicken thighs in the air fryer, skin side down, for 12 minutes.
Turn your chicken thighs skin side up and cook for 10-15 minutes more. If you would like your chicken thighs super crispy, cook for 4-minute increments to get your desired crispness.
The crispy air fryer chicken thighs are done when an internal meat thermometer reads 165°F (74°C) inserted into the thickest part of the thigh. The cooking time will vary depending on the size of your chicken thighs and the wattage of your air fryer. Serve.