In a large pot, brown chicken on high heat with some oil for approximately 8 minutes. Drain any excess oil after frying.
Return pot to heat and add tomatoes to cooked chicken. Bring to boil on medium heat. Once boiling add coconut milk, curry paste, curry powder, sugar and salt. Return to boil with lid off. Leave for at least 30 minutes (stirring occasionally) or until sauce starts to thicken. Serve over a bed of cooked rice and with mango chutney.