Preheat the oven: Heat the oven to 375°F and lightly grease a 9-by-13-inch baking dish.
Build the rice base: Spread the uncooked rice in the baking dish and pour the chicken broth over it.
Add the chicken: Arrange the chicken pieces over the rice and season with garlic powder, onion powder, oregano, paprika, salt, and pepper.
Add the tzatziki: Spoon the tzatziki over the chicken and spread it gently across the surface.
Bake: Cover tightly with foil and bake for 40 to 45 minutes, until the rice is tender and the chicken reaches 165°F.
Finish and serve: Rest for 5 minutes, then add cucumber, feta, dill, and lemon juice.