Bring a large pot of salted water to a rolling boil and cook pasta until al dente per package directions. Reserve ½ cup of pasta water and drain the pasta.

Pat chicken dry, season with salt, pepper, and ½ tsp of Italian seasoning. In a large skillet over medium-high heat, melt 1 Tbsp of butter and sear chicken for 3-4 minutes on each side until golden and cooked through. Transfer to a plate, keeping the juices.

Lower heat to medium and add the remaining 2 Tbsp of butter to the skillet. Stir in garlic and red pepper flakes; cook for 30-60 seconds until fragrant.

Pour in chicken broth, scraping the browned bits off the bottom of the skillet. Stir in heavy cream and the remaining ½ tsp of Italian seasoning. Let it simmer gently for 2-3 minutes to thicken slightly.

Reduce heat to low. Gradually sprinkle in Parmesan, stirring until it melts fully and the sauce becomes velvety smooth.

Return chicken and its juices to the skillet. Add the drained pasta and toss until the pasta is evenly coated. If the sauce is too thick, stir in splashes of reserved pasta water until it becomes glossy and clings to the pasta.

Taste and adjust salt and pepper. Garnish with chopped parsley and serve immediately.