Bring a large pot of salted water to a boil and cook the fettuccine according to package directions; drain and set aside.
In a small bowl, mix the Italian seasoning, 1/2 teaspoon salt, and black pepper; season both sides of the chicken cutlets with the mixture.
Heat the olive oil in a large 12-inch skillet over medium-high heat. When hot, add the chicken and cook 4–6 minutes per side until golden and internal temperature reaches 165°F. Transfer chicken to a plate to rest.
Reduce heat to medium and add the butter to the same skillet. When melted, stir in the minced garlic, garlic powder, and 1/2 teaspoon salt; cook 30 seconds until fragrant.
Sprinkle the flour over the butter mixture and whisk until the raw flour is blended in and no lumps remain.
While whisking constantly, slowly pour in the whole milk and heavy whipping cream and continue whisking until smooth.
Bring the sauce to a low boil, then reduce heat to low and simmer 2–3 minutes, whisking often, until the sauce thickens.
Whisk in the grated Parmesan until fully incorporated, then remove the skillet from the heat.
Add the cooked fettuccine to the Alfredo sauce and toss until the pasta is fully coated.
Slice the rested chicken cutlets into strips and arrange them over the sauced fettuccine; sprinkle with chopped parsley and serve.