Cook the fettuccine according to package instructions until al dente; drain and set aside.
Season the chicken breasts evenly with Cajun seasoning.
Heat olive oil in a large skillet over medium-high heat.
Add the chicken to the skillet and cook for 6-7 minutes per side until cooked through.
Remove chicken from the skillet and let it rest before slicing it into strips.
In the same skillet, add minced garlic and sauté for about 30 seconds.
Pour heavy cream into the skillet and bring to a simmer.
Stir in Parmesan cheese until the sauce is smooth and creamy.
Add the cooked fettuccine to the sauce, tossing to coat evenly.
Top with sliced chicken and garnish with fresh parsley before serving.