For the Calypso® Mango Chutney, combine the mango, onions chilli, garlic, ginger and salt in a large, wide, non-stick frying pan over medium. Cook, stirring occasionally for 8 minutes or until the mango starts to soften. Add the sugar and vinegar, bring to the boil, stirring often until the sugar has dissolved. Boil, stirring occasionally, for 8-10 minutes or until the chutney has thickened. Remove from the heat, stir in the nigella seeds. Spoon the hot chutney into hot sterilized jars, seal. Set aside at room temperature to cool.