In a mixing bowl, combine soy sauce, sesame oil, rice vinegar, garlic, ground ginger, and brown sugar (if using).

Add the cubed chicken breast and chopped vegetables (zucchini, squash, and carrot) to the bowl. Toss to coat evenly in the marinade.

Preheat the air fryer according to manufacturer instructions.

Place the marinated chicken and vegetables in the air fryer basket in a single layer.

Cook at the appropriate temperature for 15 minutes or until the chicken is cooked through and the vegetables are tender, shaking the basket halfway through cooking.

Once done, transfer to a serving dish and garnish with sesame seeds.