Preheat oven to 375°F (190°C) and lightly coat a 9x13 inch baking dish with non-stick spray.
In a large mixing bowl, whisk together the Greek yogurt, blended cottage cheese, minced garlic, onion powder, salt, and pepper.
Add the shredded chicken, chopped artichoke hearts, and squeezed spinach to the bowl, folding until the protein and vegetables are thoroughly coated.
Transfer the mixture into the prepared baking dish and level the surface with a spatula.
Evenly distribute the shredded mozzarella and grated parmesan over the top of the mixture.
Bake for 25 to 30 minutes, or until the cheese is golden-brown and the internal temperature reaches 165°F (74°C).
Allow the casserole to rest for 5 minutes at room temperature before portioning and serving.