Cook the fettuccine pasta according to the package instructions until al dente. Drain and set aside, reserving about 1/2 cup of the pasta water.

While the pasta is cooking, preheat your grill or grill pan over medium-high heat. Brush the chicken breasts with olive oil and season with salt and black pepper.

Grill the chicken for about 6-7 minutes on each side, or until the internal temperature reaches 165°F (75°C). Remove from the grill and let it rest for a few minutes before slicing it thinly.

In a large skillet over medium heat, melt the butter. Add the heavy cream and stir well, allowing it to come to a gentle simmer.

Stir in the garlic powder, nutmeg (if using), and season with salt and pepper. Let the sauce simmer for 3-4 minutes until slightly thickened.

Add the grated Parmesan cheese to the skillet and stir until it melts and the sauce becomes smooth and creamy.

Toss the cooked fettuccine in the Alfredo sauce, adding a bit of reserved pasta water if the sauce is too thick.

Serve the fettuccine Alfredo topped with the sliced grilled chicken and a sprinkle of chopped parsley.