Heat the oil and brown chicken breasts for about 4 minutes on each side. Remove from the pan.
Add the spring onions, chilli, celery and red pepper, and fry, stirring constantly, for 5 minutes or until the vegetables are slightly softened. Add sliced mushrooms and cook for about 2 minutes.
Return the chicken to the pan and stir in the garlic, fennel seeds, ground coriander, cumin and turmeric. Cook for 1 minute. Add the tomatoes with their juice, and the coconut milk. Bring to the boil, then reduce the heat and cover the pan. Simmer for 5 minutes.
Stir in the water chestnuts and lime juice.
Serve with hot rice, and garnish with a sprinkle of chopped fresh coriander.