Bring a large pot of salted water to a boil and cook rotini according to package instructions until al dente; reserve 1/2 cup pasta water and drain.

Toss the cubed chicken breast with 2 tablespoons of Cajun seasoning until evenly coated.

In a large skillet over medium-high heat, melt the butter and sear the chicken until golden brown and cooked through, approximately 6-8 minutes. Remove chicken and set aside.

In the same skillet, reduce heat to medium and add minced garlic, sautéing for 60 seconds until fragrant.

Pour in the heavy cream and remaining 1 tablespoon of Cajun seasoning, scraping the bottom of the pan to deglaze.

Add cubed Velveeta and stir constantly until the cheese is fully melted and the sauce is smooth.

Gradually whisk in the shredded mozzarella until incorporated and the sauce achieves a thickened consistency.

Fold the cooked rotini and seared chicken into the sauce, adding reserved pasta water as needed to adjust viscosity.

Garnish with chopped parsley and serve immediately.