Preheat your oven to 375°F (190°C) and lightly grease a baking dish.
In a large mixing bowl, combine the cooked rice, cooked chicken, mayonnaise, sour cream, Parmesan cheese, mozzarella cheese, parsley, green onions, garlic, oregano, basil, salt, and black pepper. Mix well until all the ingredients are evenly combined.
Transfer the mixture into the prepared baking dish and spread it out in an even layer.
Place the baking dish in the preheated oven and bake for about 25-30 minutes, or until the top is golden brown and the mixture is heated through.
Once it's done, remove the dish from the oven and let it cool for a few minutes before serving.
Serve the chicken mayo rice bake as a main course or as a side dish. It pairs well with a fresh salad or steamed vegetables.
Enjoy your delicious chicken mayo rice bake!