Bring a large pot of salted water to a boil. Cook the rotini according to package directions until al dente, usually 9-10 minutes. Drain well and set aside. Do not rinse.

While the pasta cooks, heat olive oil in a large 12-inch skillet over medium-high heat.

Toss the chicken chunks with Cajun seasoning, garlic powder, onion powder, salt, and pepper in a bowl until evenly coated.

Add the seasoned chicken to the hot skillet in a single layer. Cook for 6-7 minutes, flipping occasionally, until browned on all sides and cooked through to 165°F internal temperature. Remove chicken from skillet and set aside.

Reduce heat to medium. Add butter to the same skillet. Once melted, add minced garlic and sauté for 1 minute, stirring constantly, until fragrant but not browned.

Pour in chicken broth and heavy cream, scraping up any browned bits from the bottom of the skillet. Bring to a gentle simmer with small bubbles breaking the surface.

Reduce heat to medium-low. Add mozzarella, Parmesan, and cheddar cheeses. Stir constantly until cheeses melt completely and sauce is smooth with no lumps, about 2-3 minutes.

Add the cooked rotini and browned chicken back to the skillet. Use tongs to toss everything together until pasta and chicken are fully coated in the cheese sauce.

Let simmer for 2-3 minutes to meld flavors and allow pasta to absorb some sauce. If sauce is too thick, add a splash of chicken broth or pasta water to loosen.

Remove from heat. Garnish with freshly chopped parsley and serve immediately while cheese is melted and creamy.