Prepare the chicken by shredding it into bite-sized pieces if using leftover cooked chicken, or cook raw chicken until it reaches an internal temperature of 165°F, then shred.
Thaw the frozen riced cauliflower and drain any excess water, or rice fresh cauliflower using a food processor or box grater.
In a large mixing bowl, combine softened cream cheese, sour cream, garlic powder, onion powder, salt, black pepper, and paprika. Blend until smooth and creamy.
Add shredded chicken and thawed riced cauliflower to the cheese sauce and mix until well combined.
Transfer the mixture to a greased 9x13-inch baking dish, spread evenly, and sprinkle remaining cheddar and mozzarella cheeses on top. Bake in a preheated oven at 350°F for 25-30 minutes until cheese is bubbly and golden brown.