Preheat the air fryer to 380°F (193°C) for 3 to 5 minutes.
Pat the chicken breasts dry with paper towels. If they are thick, pound them to an even thickness.
In a small bowl, combine the Cajun seasoning, smoked paprika, garlic powder, onion powder, thyme, oregano, cayenne pepper, salt, and black pepper.
Brush both sides of the chicken breasts with olive oil.
Coat the chicken evenly with the Cajun seasoning mixture, pressing gently so the spices stick.
Place the chicken breasts in the air fryer basket in a single layer, leaving space between each piece.
Air fry for 10 minutes, then flip the chicken.
Continue cooking for 8 to 10 minutes, or until the chicken reaches an internal temperature of 165°F (74°C).
Let the chicken rest for 5 minutes before serving.
Garnish with fresh parsley and serve with lemon wedges if desired.