Wash the chicken breasts and pat them dry with paper towels. Cut them into small bite-sized pieces and place them in a bowl.
Add soy sauce, honey, oyster sauce, cornstarch, minced garlic, minced ginger, a little salt, and black pepper to the chicken. Mix everything well until the chicken is fully coated. Let it sit for 10 minutes.
Wash the broccoli, bell pepper, and onion. Cut the broccoli into small florets, slice the bell pepper, and slice the onion into thin strips.
Heat vegetable oil in a large pan or wok over medium-high heat.
Add the marinated chicken to the hot pan. Cook for 5–6 minutes, stirring often, until the chicken turns golden brown and is fully cooked.
Add the broccoli, bell pepper, and onion to the same pan with the chicken.
Stir fry everything for 3–4 minutes until the vegetables become slightly tender but still colorful.
Taste the stir fry and add more salt or black pepper if needed.
Turn off the heat and transfer the honey garlic chicken stir fry to a serving plate.
Sprinkle sesame seeds on top before serving.
