Final answer:
The liquid Chef Aamin creates using chicken pieces, mirepoix, and sachet de épices is called chicken stock.
Step-by-step explanation:
The liquid that Chef Aamin creates using chicken pieces, mirepoix, sachet de épices, salt, and pepper is called chicken stock. Chicken stock is made by simmering chicken bones and vegetables to extract their flavors and nutrients, resulting in a rich and flavorful liquid that forms the base for many soups, sauces, and dishes.