Mix the paprika, garlic powder, onion powder, oregano, thyme, cayenne, salt, and pepper in a small bowl. Rub the mixture evenly over both sides of the chicken breasts.
Heat olive oil in a large skillet over medium-high heat. Add the seasoned chicken and cook for 5–6 minutes per side or until blackened and fully cooked through. Remove from the skillet and let rest for 5 minutes before slicing.
While the chicken cooks, bring a large pot of salted water to a boil. Cook the fettuccine according to package directions. Drain and set aside.
In the same skillet used for the chicken, melt the butter over medium heat. Add the garlic and sauté for 1 minute until fragrant. Pour in the heavy cream and bring to a gentle simmer. Stir in the Parmesan cheese and cook, stirring, until the sauce thickens—about 3–4 minutes. Season with salt and pepper.
Add the cooked pasta to the skillet with the Alfredo sauce. Toss until well coated. Add sliced blackened chicken on top.
Plate the pasta with the blackened chicken arranged on top. Garnish with chopped fresh parsley and extra Parmesan if desired.