Preheat oven to 375°F (190°C) and grease a 9x13 inch baking dish.
In a large mixing bowl, combine softened cream cheese, sour cream, and mayonnaise until smooth.
Stir in the minced garlic, onion powder, red pepper flakes, salt, and pepper.
Fold in the shredded chicken, chopped artichokes, squeezed spinach, and 1/2 cup of the Parmesan cheese.
Mix until all components are evenly distributed.
Transfer the mixture into the prepared baking dish and spread into an even layer.
Sprinkle the remaining 1/2 cup of Parmesan cheese and the mozzarella cheese over the top.
Bake for 25 to 30 minutes, or until the cheese is melted and golden brown on top.
Remove from oven and let rest for 5 minutes before serving.