Prep the zucchini: Preheat oven to 400°F (205°C). Slice zucchini lengthwise and scoop out centers, leaving a sturdy shell.
Pre-bake zucchini: Brush with olive oil, sprinkle with salt, and roast cut-side up for 10–12 minutes.
Cook the filling: Heat olive oil in a skillet over medium heat, sauté onion for 3–4 minutes, then add garlic, chicken, and spices.
Finish the filling: Cook until chicken is fully browned, then stir in olives and remove from heat.
Stuff and bake: Fill zucchini boats evenly, top with feta, and bake 15–18 minutes until heated through.
Garnish: Finish with fresh herbs and a squeeze of lemon before serving.