Marinate the Chicken: In a large bowl, combine the chicken pieces with olive oil, lemon juice, parsley, oregano, thyme, smoked paprika, cumin, garlic powder, onion powder, seasoned salt, black pepper, turmeric, and cayenne pepper. Mix well to ensure the chicken is evenly coated. Let it marinate at room temperature for 30 minutes.
Preheat the Oven: While the chicken is marinating, preheat your oven to 375°F (190°C).
Assemble the Casserole: Lightly grease a 9x13-inch baking dish. Spread the uncooked rice evenly across the bottom of the dish.
Sprinkle the grated zucchini over the rice. Pour the chicken broth over the rice and zucchini.
Arrange the marinated chicken pieces on top.
Bake: Cover the baking dish tightly with aluminum foil. Bake in the preheated oven for 40 minutes, or until the rice is tender and the chicken is cooked through. If the rice isn't fully cooked after 40 minutes, re-cover and bake for an additional 5-10 minutes.
Prepare the Tzatziki Sauce: While the casserole is baking, prepare the tzatziki sauce. In a medium bowl, combine the Greek yogurt, grated cucumber, lemon juice, minced garlic, dill, salt, and olive oil. Stir until well blended. Refrigerate until ready to serve.
Serve: Once the casserole is done, remove it from the oven and let it rest for 5 minutes. Fluff the rice with a fork. Serve the chicken and rice topped with the homemade tzatziki sauce.