Cook pasta according to package; drain and set aside. Reserve 1/2 cup pasta water.
Season chicken with half the Cajun seasoning. Sear in oil over medium-high heat until browned and cooked through; remove.
Add sausage to pan and brown briefly. Remove with chicken.
Sauté onion and pepper until soft, 4–5 minutes. Add garlic and remaining Cajun seasoning; cook 30 seconds.
Pour in broth and cream, bring to simmer, then stir in cheese until melted.
Return chicken and sausage to pan. Toss with pasta, add reserved pasta water if needed to loosen sauce. Adjust salt and pepper.
Garnish with parsley and serve hot.