01 - Bring a large pot of salted water to a boil. Cook the fettuccine according to package instructions until al dente. Reserve 1/2 cup pasta water, then drain and set aside.
02 - While the pasta cooks, pat the chicken breasts dry with paper towels. Season both sides generously with salt and pepper.
03 - Heat olive oil in a large skillet over medium-high heat. Add chicken breasts and cook for 5-6 minutes per side until golden brown and cooked through. Remove to a plate, let rest for 5 minutes, then slice thinly.
04 - In the same skillet, reduce heat to medium. Add butter and minced garlic. Sauté for 1 minute until fragrant but not browned.
05 - Pour in heavy cream and bring to a gentle simmer. Stir in Parmesan cheese until melted and smooth. Add nutmeg if using. Season with salt and pepper to taste.
06 - Add the cooked pasta to the skillet and toss to coat in the sauce. If the sauce is too thick, add reserved pasta water a little at a time to reach desired consistency.
07 - Add sliced chicken to the pasta and gently toss. Serve hot, garnished with chopped parsley and extra Parmesan.