Cut the chicken tenderloin into bite-sized pieces.
Wash the napa cabbage and bean sprouts, then drain well.
Heat cooking oil in a pan and stir-fry the chicken tenderloin.
When the chicken is halfway cooked, add the napa cabbage and stir-fry together.
Once the cabbage softens, add the bean sprouts and stir-fry quickly over high heat.
Season with salt and pepper.