In a large pot, bring salted water to a boil. Add the penne pasta and cook according to package instructions until al dente. Drain and set aside.

In a large skillet, heat olive oil over medium heat. Add the diced chicken and cook until browned and cooked through, about 5-7 minutes. Remove from the skillet and set aside.

In the same skillet, add the sliced Cajun sausage and cook for about 3-4 minutes until browned.

Stir in the chopped onion, garlic, and bell pepper. Sauté for an additional 3-4 minutes until the vegetables are softened.

Return the cooked chicken to the skillet. Add the drained diced tomatoes, heavy cream, Cajun seasoning, salt, and pepper. Stir to combine and let simmer for 2-3 minutes.

Fold in the cooked penne pasta, then mix in half of the cheddar and mozzarella cheese until melted and well combined.

Preheat your oven to 350°F (175°C). Pour the pasta mixture into a greased 9x13-inch casserole dish. Sprinkle the remaining cheddar and mozzarella cheese on top.

Bake in the preheated oven for 20-25 minutes, or until the cheese is bubbly and golden brown.

Remove from the oven and let cool for a few minutes. Garnish with chopped fresh parsley before serving.