Preheat oven to 220°C. Line a large baking tray with baking paper.
Lay chicken on tray and drizzle with half the oil. Sprinkle with seasoning and toss to coat. Add capsicum and onion to tray. Drizzle with remaining oil. Bake for 20-25 minutes or until chicken is cooked through and vegetables are tender.
Meanwhile, slice jalapeño. Combine half with yoghurt and juice in a small bowl. Top chicken with avocado, coriander and remaining jalapeño. Serve with yoghurt, warm tortillas and lime wedges.