Cook the Pasta: Bring a large pot of salted water to a boil. Add the rotini pasta and cook until al dente according to package directions, usually 8-10 minutes. Be careful not to overcook as the pasta will continue to soften slightly when combined with the sauce later. Once cooked, drain thoroughly and set aside.

Sauté the Chicken: Heat olive oil in a large skillet over medium-high heat until shimmering. In a bowl, toss the chicken pieces with Cajun seasoning, garlic powder, onion powder, salt, and pepper until evenly coated. Add the seasoned chicken to the hot skillet, arranging in a single layer if possible. Cook for 6-7 minutes, turning occasionally until the chicken is golden brown on the outside and no longer pink in the center. Transfer the cooked chicken to a plate and set aside.

Make the Cheesy Sauce: Using the same skillet (no need to clean it), reduce heat to medium and add the butter. Once melted, add minced garlic and sauté for about 1 minute until fragrant but not browned. Pour in the chicken broth, using a wooden spoon to scrape up any flavorful browned bits from the bottom of the pan. Add the heavy cream and bring the mixture to a gentle simmer. Gradually add the mozzarella, Parmesan, and cheddar cheeses, stirring constantly until completely melted and the sauce is smooth and velvety.

Combine Everything: Return the cooked chicken to the skillet, then add the drained pasta. Gently toss everything together until the pasta and chicken are fully coated in the creamy Cajun cheese sauce. Allow the mixture to simmer for 2-3 minutes to let the flavors meld together and the sauce slightly thicken. If the sauce seems too thick, add a splash of chicken broth or water to reach your desired consistency.

Serve: Remove the skillet from heat. Taste and adjust seasoning if necessary. Garnish generously with freshly chopped parsley and additional cheese if desired. Serve immediately while hot and creamy for the best texture and flavor experience.