Coat a large non-stick fry pan with cooking spray and cook the chicken breast fillets for 5 minutes each side. Pour over the lemon juice during the last minute of cooking. Transfer to a plate, cover with foil and keep warm while you make the fritters.
Place the grated sweet potato, shallots and ginger in a large mixing bowl and combine. Stir through the egg and flour.
Recoat the pan with cooking spray and heat. Scoop a quarter of the mixture into the pan and form into a circle about 12cm in diameter. Cook over a low heat for 4 minutes on each side or until golden and cooked. Remove from the pan and keep warm while cooking the remaining fritters.
Divide the fritters between 4 serving plates. Cut the chicken into slices and place on top of the fritters. Spoon over the sweet chili sauce and scatter with coriander, if using.