Prepare the chicken by cutting it into bite-sized pieces and tossing with Cajun seasoning.
Cook the penne pasta in salted boiling water until al dente, about 8-10 minutes. Drain and set aside.
In a large skillet, heat olive oil over medium-high heat. Cook the seasoned chicken for 5-7 minutes until browned and cooked through. Remove and set aside.
In the same skillet, sauté diced onion and bell pepper for 3-4 minutes until softened. Add minced garlic and cook for an additional minute.
Pour in chicken broth and bring to a simmer. Reduce heat to low, stir in heavy cream and Parmesan cheese until melted and creamy.
Return the cooked chicken to the skillet, add the drained pasta, and toss until well combined. Season with salt and pepper to taste.
Serve immediately, garnished with fresh chopped parsley.