Place the sweet potatoes into a saucepan and fill with enough water to cover. Simmer over medium-high heat until tender; about 10 minutes. Drain and set aside.
Meanwhile; heat 2 tablespoons of vegetable oil in a frypan over medium-high heat. Stir in chicken and cook until no longer pink in the centre: about 5 minutes. Set aside.
Stir garlic into the frypan and cook for a few minutes until fragrant. Pour in the tamari, 3/4 cup of water, honey and tabasco.
Bring to a simmer then stir in the sweet potato, chicken, mango and chilli flakes. Cook and stir until hot. Dissolve the cornflour in 1 tablespoon of water and stir into the simmering mixture; stir until thickened.