Cook the fettuccine: Bring a large pot of salted water to a boil. Add the fettuccine and cook according to package instructions until al dente. Reserve 1 cup of pasta water, then drain the pasta and set aside.

Prepare the chicken: Season the chicken breasts with Italian seasoning, garlic powder, salt, and pepper. Heat olive oil in a large skillet over medium heat. Add the chicken and cook for 4-5 minutes per side, or until golden brown and cooked through (internal temperature of 165°F / 74°C). Remove the chicken from the skillet, let it rest for 5 minutes, and slice into thin strips.

Make the Alfredo sauce: In the same skillet used for the chicken, melt the butter over medium heat. Add the minced garlic and sauté for about 1 minute, until fragrant. Pour in the heavy cream and let it simmer gently for 2-3 minutes. Reduce the heat to low and whisk in the grated Parmesan cheese until melted and smooth. Add nutmeg (if using) and season with salt and pepper to taste. If the sauce is too thick, stir in some reserved pasta water to loosen it.

Combine the pasta and sauce: Add the cooked fettuccine to the skillet with the Alfredo sauce. Toss gently to coat the pasta evenly. Add more pasta water if needed to achieve your desired consistency.

Assemble the dish: Plate the fettuccine Alfredo and top with the sliced chicken. Garnish with additional Parmesan cheese, chopped parsley, and cracked black pepper if desired.

Serve immediately with a side of garlic bread or a fresh salad.