Begin by bringing a large pot of salted water to a rolling boil. Add the fettuccine and cook according to the package instructions until al dente. Drain and set aside.

In a large skillet over medium heat, add olive oil. Once hot, add the sliced chicken breast. Sprinkle with Cajun seasoning, salt, and pepper. Cook until the chicken is golden brown and cooked through, about 6-8 minutes.

Lower the heat and pour in the chicken broth, then add the heavy cream and diced tomatoes. Stir well, allowing the mixture to simmer for about 5 minutes.

Add the cooked fettuccine to the skillet, tossing it gently in the sauce until well coated. If the pasta seems too dry, add a splash more chicken broth.

Stir in the grated Parmesan cheese until melted, and garnish with chopped parsley before serving.