Trim the roots and tops off the spring onions and slice diagonally. Peel and grate the ginger and crush or finely chop the garlic. Cut the mango lengthways on either side of the stone, then peel off the skin and chop the flesh into cubes. Slice the chicken into thin strips.
Heat half the oil in a large frying pan or wok. Add the chicken and stir-fry for 4-5 minutes until lightly coloured. Remove from the pan with a slotted spoon and transfer to a plate. Heat the remaining oil in the pan and add the spring onions, ginger and garlic. Stir-fry for 30 seconds, then add the mango and vegetables and stir-fry for a further 1 minute.
Return the chicken to the pan and splash in the soy and chilli sauces. Stir until evenly mixed, then cover and cook for a further 2 minutes until the chicken is tender and the veggies are slightly softened.