Bring a large pot of salted water to a rolling boil and start cooking the rotini pasta according to package directions until al dente, typically 8-10 minutes. Reserve ½ cup pasta water before draining, then set pasta aside.

While pasta cooks, heat olive oil in a large skillet over medium-high heat. Season chicken chunks with Cajun seasoning, garlic powder, onion powder, salt, and pepper, tossing to coat evenly.

Add seasoned chicken to the hot skillet in a single layer. Cook for 6-7 minutes, stirring occasionally, until chicken is golden brown and reaches an internal temperature of 165°F. Remove chicken and set aside.

In the same skillet, melt butter over medium heat. Add minced garlic and sauté for 1 minute until fragrant - watch carefully to prevent burning.

Pour in chicken broth and heavy cream, whisking to combine. Bring mixture to a gentle simmer (small bubbles around edges), then gradually add mozzarella, Parmesan, and cheddar cheeses, stirring constantly until smooth and melted.

Return cooked rotini and chicken to the skillet, tossing everything together to coat evenly in the cheesy Cajun garlic sauce. Simmer for 2-3 minutes to meld flavors. Add reserved pasta water if sauce seems too thick. Garnish with fresh parsley and serve immediately.