Bring a large pot of salted water to a boil. Cook the fettuccine according to package instructions for 8-12 minutes. Reserve about a cup of pasta water before draining.

Heat a skillet over medium-high heat with olive oil. Add chicken seasoned with Cajun seasoning. Sauté for 6-8 minutes until golden brown and cooked through.

Reduce heat to medium-low, pour in heavy cream and add Parmesan cheese. Stir until melted and smooth, about 3-4 minutes.

Add drained fettuccine to the skillet, tossing until coated in sauce. Add reserved pasta water if sauce is too thick.

Serve hot, garnished with parsley or green onions, alongside salad or garlic bread.