Cook pasta according to package directions until al dente. Drain and set aside.
Toss chicken strips with 1 tablespoon Cajun seasoning, salt, and pepper.
In a large skillet, heat olive oil over medium-high heat. Add chicken and sear for 4–5 minutes per side until golden and cooked through. Remove and set aside.
In the same skillet, reduce heat to medium. Add butter and garlic, sauté for 30 seconds.
Stir in cream, chicken broth, and remaining Cajun seasoning. Simmer for 2–3 minutes.
Add parmesan cheese and stir until the sauce thickens slightly. Add tomatoes or peppers if using, and cook another minute.
Return cooked chicken and pasta to the skillet. Toss to coat in the creamy Cajun sauce.
Garnish with parsley and serve immediately.