Heat olive oil in a pan over medium heat. Add chicken, season with salt and pepper, and cook for 5–10 minutes until lightly browned and mostly cooked through. Add a splash of water if needed.
1.2 lb chicken breast or chicken thighs, 2 tablespoon olive oil, Salt, Black pepper
Add chopped onion and sliced mushrooms, and crumble the chicken stock. Stir well, cover with a lid, and cook until the mushrooms soften and release their juices, then reduce down.