Prepare the chicken by boiling or baking until fully cooked, then shred or dice into bite-sized pieces.
Sauté the chopped spinach in a medium skillet with olive oil over medium heat for 2-3 minutes until wilted.
In a large mixing bowl, combine cream of chicken soup and sour cream, then add garlic powder, onion powder, salt, black pepper, and paprika. Mix until smooth.
Add shredded chicken, sautéed spinach, and cooked rice to the creamy sauce and fold gently until well combined.
Transfer the mixture to a greased 9x13 inch baking dish, spread evenly, and top with breadcrumbs mixed with olive oil if using. Bake in a preheated oven for 25-30 minutes until bubbly and golden brown.
Let the casserole cool for 5 minutes before serving.