Bring a large pot of salted water to a boil and cook the rigatoni according to package directions until al dente.
While the pasta cooks, season the chicken pieces with Italian seasoning, salt, and pepper.
Heat olive oil in a large skillet over medium-high heat and sear the chicken until golden brown and cooked through; remove from the skillet and set aside.
In the same skillet, melt the butter over medium heat.
Add the minced garlic and sauté for about 1 minute until fragrant.
Pour in the chicken broth and heavy cream, bringing the mixture to a gentle simmer.
Stir in the Parmesan cheese until melted and the sauce begins to thicken slightly.
Stir in the red pepper flakes and return the chicken to the skillet.
Add the cooked pasta to the sauce, tossing until well-coated.
Garnish with fresh parsley before serving.