Bring a large pot of salted water to a boil. Cook the pasta according to package directions until al dente. Reserve about 1/2 cup of pasta water, then drain.
While the pasta cooks, season the chicken with Italian seasoning, paprika, salt, and black pepper.
Heat the olive oil in a large skillet over medium-high heat. Add the chicken and cook for about 5–7 minutes, stirring occasionally, until browned and cooked through to 165°F. Transfer the chicken to a plate.
Reduce the heat to medium. Add the butter to the same skillet, followed by the minced garlic. Cook for about 30–60 seconds, stirring frequently, until fragrant.
Pour in the chicken broth and gently scrape up the flavorful browned bits from the bottom of the skillet.
Stir in the heavy cream and optional red pepper flakes. Reduce the heat and let the sauce gently simmer for 2–3 minutes.
Gradually stir in the Parmesan until melted and the sauce is smooth and creamy. Avoid bringing the sauce to a hard boil.
Return the cooked chicken to the skillet, then add the drained pasta. Toss until everything is evenly coated. Add a splash of reserved pasta water if the sauce needs thinning.
Taste and adjust the salt and pepper as needed. Sprinkle with fresh parsley and additional Parmesan before serving.