In the same pan, melt remaining butter, add garlic, and cook until fragrant. Stir in heavy cream, chicken broth, Parmesan, cream cheese, Italian seasoning, basil, and red pepper flakes. Simmer until slightly thickened.
Add cooked chicken and spaghetti to the sauce, stirring to combine. Top with shredded cheeses and cook until melted. Garnish with parsley before serving.
Notes
For extra spice, increase Cajun seasoning and red pepper flakes to taste.