Saute small onion ,when it get littile brown
Add garlic and ginger,green chilly.
Saute again and add turmeric and coriander powder and garam masala.
Add chicken to it along with coconut thin milk.
Cook for 30 mins in a low flame.
After the chicken is cooked properly add thick coconut milk and salt.
Heat few oil in a small tava for making tadka.
Add mustard ,curry leaves ,coconut pieces ,red chilly.
Switch off the flame and add chilly powder .
Add this tadka to the chicken.