Cook the fettuccine pasta according to package instructions until al dente. Drain and set aside.
In a large bowl, toss the chicken pieces with Cajun seasoning until evenly coated.
In a large skillet, heat the olive oil over medium-high heat. Add the seasoned chicken and cook for about 5-7 minutes, or until browned and cooked through. Remove the chicken from the skillet and set aside.
In the same skillet, add the diced onion and sliced bell pepper. Sauté for 3-4 minutes until softened. Add the minced garlic and cook for an additional 1 minute.
Pour in the chicken broth and bring to a simmer. Stir in the heavy cream and let it cook for 2-3 minutes until slightly thickened.
Add the cooked chicken back into the skillet, then stir in the grated Parmesan cheese until melted and creamy. Season with salt and pepper to taste.
Toss the cooked fettuccine pasta into the sauce, ensuring the pasta is well coated. Cook for an additional 1-2 minutes to heat through.
Serve immediately, garnished with fresh parsley.