Heat sesame oil in a large pan or wok over medium-high heat.
Add sliced chicken breast and cook until browned, about 5 minutes.
Add minced garlic and ginger, stirring for 1 minute.
Toss in the mixed vegetables and stir-fry for 3-4 minutes until tender-crisp.
Drizzle soy sauce and oyster sauce over the mixture.
Stir well to combine and cook for another 2 minutes.
Add sliced green onions and mix thoroughly.
Remove from heat and sprinkle with sesame seeds.
Serve hot over cooked rice or noodles.
Enjoy your delicious chicken stir fry!