Bring a large pot of salted water to a boil. Add the pasta and cook until al dente. Reserve some pasta water.
Season the chicken breasts generously with Cajun seasoning, garlic powder, onion powder, salt, and pepper.
Heat 2 tablespoons of butter in a large skillet over medium-high heat. Add the chicken and cook for about 4 minutes on each side until golden brown. Remove from the skillet and set aside.
In the same skillet, add the remaining 2 tablespoons of butter and the diced onion. Sauté for about 4 minutes until softened.
Add a splash of reserved pasta water and a small amount of Knorr Chicken Flavor Seasoning. Stir to combine.
Reduce the heat to medium and pour in the heavy cream. Let it gently simmer.
Add the mozzarella and parmesan cheese. Stir until melted and smooth.
Season the sauce with additional Cajun seasoning, salt, and pepper to taste.
Add the cooked pasta into the sauce and stir until fully coated.
Slice the cooked chicken and serve it over the pasta. Enjoy!