In a hot pan add oil, mustard seeds, curry leaves, on crackling add onion, dried basil, cumin, chili flakes, turmeric and salt.
Pour coconut milk Increase heat to medium-high Boil uncovered and stirring often, until sauce is reduced by one thirds, about 4 to 5 minutes.
Marinate chicken in salt and add to pan chicken Reduce heat to medium.
Add mango and stir often, uncovered, until chicken is cooked, squeeze juice from half of lime over top. Sprinkle with On1y basil. Serve with lime wedges.