Cut the chicken breast into bite-sized pieces.
Wash the bean sprouts thoroughly.
Julienne the onion.
Drizzle olive oil in a pan and preheat over medium heat.
Add the chicken breast and cook on both sides until done.
Add the onions and stir-fry.
Add the bean sprouts and quickly stir-fry over high heat.
Season with salt and black pepper.
Turn off the heat and serve on a plate.