Cut the chicken breast into bite-sized pieces.
Thinly slice the onion and green onion.
Heat olive oil in a pan and stir-fry the chicken breast.
When the chicken is cooked, add the onion and green onion and stir-fry together.
Season with soy sauce, oyster sauce, and pepper.
Place the stir-fried ingredients over rice, then drizzle with sesame oil and sprinkle with sesame seeds.