Blanch the chicken drumsticks in boiling water, then rinse them to remove any impurities.
Put the drumsticks, tomatoes, lily buds, chestnuts, shiitake mushrooms, chicken stock, shaoxing, oyster sauce and sea salt into a large heatproof bowl. Cover the bowl tightly with foil and put in a bamboo steamer over a pot or wok of rapidly boiling water. Cover and steam for 50 minutes. Remove the chicken from the bowl and set aside to cool slightly. Remove the skin, then shred the meat from the bones. Stir the chicken meat, noodles, spring onion and coriander through the soup and ladle into bowls to serve.