In a large pot of boiling salted water, cook pasta according to package instructions; drain well.

Melt 1 tablespoon butter in a large skillet over medium high heat. Season chicken with Italian seasoning, salt and pepper, to taste. Add chicken to the skillet and cook, flipping once, until cooked through, about 3-4 minutes per side. Let cool before slicing; set aside.

Melt remaining 3 tablespoons butter in the skillet. Add garlic, and cook, stirring frequently, until fragrant, about 1-2 minutes. Whisk in flour, tomato paste and basil until lightly browned, about 1 minute.

Gradually whisk in milk and sun-dried tomatoes. Cook, whisking constantly, until slightly thickened, about 5 minutes. Stir in cream cheese and Parmesan until smooth, about 1-2 minutes. If the mixture is too thick, add more milk as needed; season with salt and pepper, to taste.

Stir in pasta and chicken, and gently toss to combine.

Serve immediately, garnished with Parmesan and parsley, if desired.