Bring a large pot of water to a boil, and salt generously. Add the pasta, and boil according to package directions. Strain, and toss with a splash of oil.
Meanwhile, slice the chicken into 1/4-inch-thick strips, season with salt and pepper.
Heat a large skillet over medium heat, and add 2 tablespoons of the butter. When the butter melts, raise the heat to medium-high and add the chicken in 1 layer. Cook, without moving the pieces, until the underside has browned, 1 to 2 minutes. Flip the pieces, and cook until browned and fully cooked through, 2 to 3 minutes more. Transfer the chicken to a medium bowl.
Reduce the heat to medium, and add the alfredo sauce. Scrape the bottom of the skillet with a wooden spoon to release any browned bits.
When the sauce has warmed through, add the chicken and cooked pasta, and toss well. Season with salt and pepper. Serve hot with freshly grated parmesan on top.
