Cut chicken into three 4 inch pieces.
Seed, core and cut peppers into 1-inch pieces.
Slice onions into 1 ½-inch lengths.
Peel and pit mangoes and cut into ⅔-inch pieces.
Whisk together stock, sugar, soy sauce, vinegar, cornstarch and curry paste.
In wok or skillet heat half of the oil over high heat; stir fry chicken for 4 minutes or until no longer pink inside.
Transfer to plate.
Add remaining oil to wok; stir-fry peppers for 2 minutes.
Stir in ginger, cook for 30 seconds.
Add stock mixture and chicken, cook stirring for 2 minutes or until sauce is thickened and chicken is hot.
Stir in onions and mango.
Sprinkle with cashews (if using).
