Preheat the oven to 375F. Add chicken thighs to a baking dish. Drizzle with oil and add spices then toss to combine and coat the chicken. Arrange the seasoned thighs evenly in the dish.
Dump the rice, chicken broth, garlic, lemon juice and zest, and herbs/spices into the baking dish with the chicken. Ensure all of the rice is covered with liquid for even cooking.
Add the tomatoes and chopped zucchini, followed by feta cheese sprinkled on top.
Cover the baking dish with foil and bake, covered, at 375F for 40-45 minutes, then remove foil and bake for another 15-20 minutes. (Note: It's normal if not all of the liquid is absorbed when you remove the foil. It will continue to absorb in the last 15-20 minutes of cooking!)
Dish out and serve topped with tzatziki, thinly sliced red onion, and more feta cheese.