Prepare the Marinade. In a bowl, combine soy sauce, brown sugar, sesame oil, minced garlic, grated ginger, gochujang, and rice vinegar. Mix well until the sugar is dissolved.
Marinate the Chicken. Cut the chicken thighs into bite-sized pieces. Add the chicken to the marinade, ensuring each piece is well-coated. Cover and refrigerate for at least 20 minutes.
Preheat the Air Fryer. Preheat your air fryer to 375°F.
Air Fry the Chicken. Place the marinated chicken pieces in the air fryer basket in a single layer. Cook for 10 minutes, then shake the basket or flip the chicken pieces. Cook for an additional 8-10 minutes, or until the chicken is cooked through and slightly caramelized.
Serve. Transfer the cooked chicken bulgogi to a serving platter. Garnish with sliced green onions and sesame seeds. Serve hot with steamed rice or lettuce wraps.