Preheat the oven to 375°F (190°C).
Cook pasta according to package directions. Drain and set aside.
In a skillet, heat olive oil over medium heat and cook diced chicken with Cajun seasoning until fully cooked.
In a large bowl, combine cream cheese, cheddar cheese, Parmesan, milk, and sour cream. Mix until smooth.
Add cooked pasta and chicken into the bowl and stir to coat evenly.
Transfer mixture to a greased baking dish and bake for 20–25 minutes or until bubbly and golden.
Garnish with chopped green onions if desired, and serve hot.