In a small bowl, mix together the balsamic vinegar, honey, honey mustard, minced garlic, salt, and black pepper until well combined to form a sauce.
Place the chicken thighs in a single layer in an air fryer-safe (oven-safe) pan, making sure they aren’t overlapping.
Pour the prepared balsamic marinade from Step 1 evenly over the chicken thighs in the pan, ensuring they are well coated. I like to gently lift each thigh to let some of the sauce get underneath for extra flavor.
Place the pan in the air fryer. Set the air fryer to 350°F and cook for 7 minutes. After 7 minutes, open the air fryer and spoon some of the sauce from the pan over the chicken for extra moisture, then cook for an additional 7 minutes. Check that the internal temperature of the chicken reaches at least 165°F. If not, air fry for up to 5 minutes more as needed.
Transfer the cooked chicken thighs to plates, spooning some of the extra sauce over the top. Enjoy your meal!