Heat the oil in a saucepan and add the onion and garlic, cook on a medium heat until softened then add the chicken and brown the meat until cooked through. Stir in the milk, then stir in the remaining ingredients, adding the mozzarella in handfuls whilst stirring.

Boil a saucepan of water and start cooking your pasta. Keep the chicken pesto sauce on a low heat stirring until the cheese has completely melted and is not stringy. Serve over the pasta and enjoy!