Bring a large pot of salted water to a boil. Add the fettuccine and cook according to package instructions until al dente. Drain and set aside.

Season the chicken breasts with salt and black pepper.

In a skillet, heat olive oil over medium-high heat. Add the chicken breasts and cook for about 5-7 minutes on each side until golden brown and cooked through. Remove from skillet and set aside.

In the same skillet, add sliced mushrooms and cook until browned, about 5 minutes.

Add minced garlic and cook for an additional minute until fragrant.

Pour in the Marsala wine and chicken broth, scraping up any browned bits from the bottom of the skillet. Bring to a simmer and let it reduce for about 10 minutes.

Stir in the butter until melted and smooth.

Slice the cooked chicken and return it to the skillet with the sauce. Add the cooked pasta and toss to combine.

Serve hot, garnished with chopped parsley.