Bring a large saucepan of salted water to the boil. Add the tagliatelle and cook until al dente. Drain and set aide.
Melt the butter in a large frying pan. Pan fry the chicken until almost cooked through. Remove to a bowl and set aside.
Add the Marsala wine to deglaze the pan and scrape any browned bits of chicken.
Add garlic and chilli and cook on low heat until softened.
Increase the heat, add mushrooms and stir fry for a minute.
Add stock and chicken and continue to cook for 3 – 4 minutes on a medium heat until the mushrooms are cooked through and the liquid has evaporated slightly. Stir in the chopped parsley.
Add the pasta to the sauce and mix well. Serve immediately.