Cut the chicken breast into cubes.
Finely chop the onion and bell pepper.
Heat olive oil in a pan and sauté the chicken breast.
Once the chicken breast is cooked, add the onion and bell pepper, and stir-fry together.
Slice and add mushrooms, then sauté.
Pour in milk and chicken stock, and bring to a boil.
Season with salt and pepper.
Finish by adding Parmesan cheese.