Bring a large pot of salted water to a boil. Cook fettuccine according to package directions until al dente, about 10 minutes. Reserve 1/2 cup of the pasta water, then drain and set aside.

Season chicken breasts with Italian seasoning, salt, and pepper.

Heat olive oil in a large skillet over medium-high heat. Add chicken and cook for 5 to 7 minutes undisturbed until golden brown. Flip, add 1 tablespoon butter, and cook another 5 to 7 minutes or until the internal temperature reaches 165°F.

Transfer chicken to a cutting board and let it rest for 3 minutes. Slice into 1/2-inch pieces and cover loosely with foil.

In the same skillet, reduce heat to medium-low. Add butter and heavy cream, whisking until butter is melted.

Add minced garlic, garlic powder, Italian seasoning, salt, and pepper. Whisk until smooth. Simmer gently for 3 to 4 minutes while whisking constantly, until slightly thickened.

Stir in Parmesan cheese and whisk just until melted and the sauce is creamy. If too thick, add some reserved pasta water.

Remove from heat and toss in the cooked pasta until evenly coated.

Serve pasta topped with sliced chicken. Garnish with extra Parmesan, parsley, and black pepper if desired.