Bring a large pot of salted water to a boil. Add the fettuccine and cook according to package directions.

Reserve 1/4 cup of pasta water, then drain and set the pasta aside.

In a bowl, season the chicken with Cajun seasoning, paprika, Italian seasoning, red pepper flakes, salt, and black pepper.

Heat olive oil in a large skillet over medium-high heat. Add the chicken and cook for 4-5 minutes on each side until it turns golden and is fully cooked.

Remove the chicken from the skillet and set aside.

In the same skillet, reduce the heat to medium and add butter. Once melted, sauté garlic for 30 seconds or until fragrant.

Pour in the heavy cream and chicken broth, then bring the mixture to a gentle simmer.

Stir in the Parmesan (and mozzarella if using), continuing to mix until the sauce is smooth and creamy.

Toss the cooked fettuccine in the creamy garlic sauce, making sure every noodle is coated. Add a splash of reserved pasta water if needed to achieve desired consistency.

Return the Cajun chicken to the skillet, allowing everything to simmer together for 1-2 minutes.

Top with chopped parsley or green onions before serving hot.