1. Pat the chicken dry and toss it with Cajun seasoning, garlic powder, smoked paprika, salt, and black pepper.

2. Heat olive oil and butter in a large skillet over medium-high heat, then cook the chicken until browned and nearly cooked through. Transfer it to a plate.

3. In the same skillet, cook the onion and bell pepper until softened, then stir in the garlic and cook for 30 seconds.

4. Pour in the chicken broth and heavy cream, then add the uncooked penne. Stir well and bring to a gentle simmer.

5. Cook the pasta, stirring often, until tender and the sauce starts to thicken.

6. Return the chicken to the skillet and stir in the diced tomatoes and Parmesan cheese.

7. Cook for another 2 to 3 minutes until the cheese melts and the sauce becomes smooth and creamy.

8. Sprinkle with chopped parsley and serve hot.