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 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 the vegetables are softened. Add the minced garlic and cook for an additional 1 minute.
Pour in the chicken broth and bring to a simmer. Reduce the heat to low and stir in the heavy cream and Parmesan cheese until the cheese is melted and the sauce is creamy.
Return the cooked chicken to the skillet and stir to combine. Add the cooked fettuccine and toss everything together until the pasta is well coated with the sauce. Season with salt and pepper to taste.
Serve immediately, garnished with fresh parsley.