Bring a large pot of salted water to a boil and cook the pasta until al dente. Reserve 1/2 cup pasta water, drain, and set aside.
Toss chicken with Cajun seasoning, smoked paprika, garlic powder, and onion powder.
Heat olive oil in a large skillet over medium-high heat. Cook chicken for 5–7 minutes until golden and fully cooked. Remove and set aside.
In the same skillet, melt butter over medium heat. Add garlic and sauté for 1 minute.
Stir in heavy cream, Parmesan cheese, chicken broth, Cajun seasoning, and red pepper flakes. Simmer 3–4 minutes until slightly thickened.
Add cooked pasta and chicken back to the skillet. Toss well to coat. Add reserved pasta water as needed for consistency.
Season with salt and black pepper. Serve hot, garnished with parsley.