Pat the chicken thighs dry and season both sides with 1 tablespoon of the Cajun seasoning, smoked paprika, salt, and pepper.
Heat olive oil in a large skillet over medium-high heat. Add the chicken and cook until browned and cooked through, about 5-6 minutes per side. Remove to a plate and set aside.
In the same skillet, add the sliced sausage and cook until browned, about 3-4 minutes. Remove with a slotted spoon and set aside with the chicken.
Reduce heat to medium. Add butter, onion, and bell pepper. Cook until softened, about 4-5 minutes. Stir in garlic and remaining 1 tablespoon Cajun seasoning; cook for 30 seconds until fragrant.
Pour in the chicken broth and scrape up any browned bits. Bring to a simmer and cook until reduced by half, about 3 minutes. Stir in heavy cream and Parmesan; simmer until slightly thickened, about 2-3 minutes.
Return the chicken and sausage to the skillet along with any accumulated juices. Simmer for 2-3 minutes to heat through and coat in the sauce. Taste and adjust seasoning.
Garnish with fresh parsley if desired. Serve hot over rice, pasta, or with crusty bread.