Cut the chicken breast into bite-sized pieces.
Slice the onion and bell pepper into thin strips.
Heat olive oil in a pan and stir-fry the chicken breast.
When the chicken is half-cooked, add the onion and bell pepper and continue stir-frying together.
Add peanut butter, soy sauce, and pepper, and stir-fry everything evenly.
Once all ingredients are cooked through, transfer to a plate and finish.