1. Combine chicken, garlic, lemon zest and half of the Italian seasoning. Season with salt and pepper.
2. Slice zucchini into rounds, slice onion into half moons. Combine zucchini with the rest of the Italian seasoning, season with salt and pepper. Sprinkle sliced onions with salt, pepper and squeeze a few drops of lemon juice.
3. Preheat oven to 400F (200C).
4. Heat olive oil in a large skillet over medium-high heat. Brown chicken for 2-3 minutes per side.
5. Add zucchini and onions, toss (make sure you use an oven proof skillet). Bake for 15 minutes, until zucchini are tender and chicken is cooked through.
8. Drizzle with some lemon juice before serving.