Soak rice for at least 20 to 30 minutes. If using normal rice (not basmati) soak it for 30 minutes.Marinate chicken using ingredients under marination. Set this aside.Add oil to a pot or pressure cooker and heat it. Add the dry spices and saute till they begin to sizzle.Add onions and fry till they turn golden. Add ginger garlic paste and fry till the raw smell goes off.Add chicken and fry till the color slightly changes to pale.Add chopped tomatoes, yogurt, red chili powder, corinader leaves and mint.Cook till the mixture turns thick and dry. By now the chicken should be almost cooked soft.Add the rest of the masala powder and fry till you get a nice smell.Mix together water or thin coconut milk and salt in a separate bowl. Check the salt , it must be slightly salty. Since salt is already added to marination, use little only. Pour this to a the chicken pot, bring it to a boil.Drain off the rice completely and add it to the pot or cooker.Cook till the water very little is left. Cover the pot or pressure cooker with a lid. Turn on the flame to very low. If using basmati rice, cook it for about 3 to 5 minutes, do not let it whistle. If using normal rice that is slightly on the harder side to cook allow it to whistle once. If cooking in pot, cook until the rice is done. If rice is under cooked, you can also sprinkle little water and cook further.Let the pressure go down. Fluff up the rice with a fork. Or transfer it immediately to a wide utensil to prevent turning mushy.If desired you can drizzle one spoon of ghee, coriander leaves and roasted boiled eggs.Serve chicken biryani with onion raita or biryani shorba or sherva.