Whisk together the honey, soy sauce, garlic, rice vinegar, sesame oil, cornstarch, and water in a small bowl. Set aside.
Heat the vegetable oil in a large skillet or wok over medium-high heat.
Add the chicken pieces and cook for 6 to 8 minutes until browned and fully cooked. Transfer the chicken to a plate.
Add the broccoli, carrots, onion, bell pepper, and mushrooms to the skillet.
Stir-fry the vegetables for 5 to 6 minutes until they are crisp-tender.
Stir in the garlic and fresh ginger and cook for about 30 seconds until fragrant.
Return the cooked chicken to the skillet.
Pour the honey garlic sauce over the chicken and vegetables.
Cook for 2 to 3 minutes, stirring frequently, until the sauce thickens and coats everything evenly.
Sprinkle with sliced green onions and sesame seeds before serving.