Begin by boiling a generous pot of salted water. Once at a rolling boil, add the fettuccine and cook until al dente, typically around 10 minutes per the package instructions. Reserve ½ cup of the starchy cooking liquid, then drain the pasta and set aside.

For the chicken, season the breasts uniformly with Italian seasoning, kosher salt, and black pepper. Heat olive oil in a large nonstick skillet over medium-high heat. When the oil shimmers, add the chicken and sear undisturbed for 5 to 7 minutes until a golden crust forms on the underside. Flip the pieces, introduce 1 tablespoon of butter, and tilt the skillet gently to evenly distribute the melting butter. Continue cooking for another 5 to 7 minutes, ensuring the internal temperature reaches 165°F. Transfer the chicken to a cutting board, let it rest for 3 minutes, then slice into ½-inch strips and tent with foil.

To prepare the Alfredo sauce, reduce the skillet heat to medium-low. Combine butter and heavy cream, whisking until the butter has fully dissolved. Add minced garlic, garlic powder, Italian seasoning, salt, and black pepper, stirring constantly to create a homogeneous mixture. Allow the sauce to simmer gently, without boiling, for 3 to 4 minutes until it thickens.

Incorporate the grated Parmesan into the sauce, stirring just until melted and smooth. Should the sauce become overly thick, gradually add reserved pasta water, a tablespoon at a time, to reach the desired consistency.

Remove the skillet from heat and immediately toss in the cooked fettuccine until thoroughly coated. Plate the pasta into individual servings, topping each with a few slices of the prepared chicken. Optionally, garnish with chopped parsley, a sprinkle of Parmesan, and freshly ground black pepper.