Heat the oil in a wok until hot. Add the chicken and stir fry until white on all sides. Drain from the oil and put aside.
Return 1 tablespoon of oil to the wok and heat. Add the peas, broccoli, green beans and capsicum then stir fry for 5 minutes. Add the garlic and return the chicken and combine, heat again until sizzling.
Add the soy sauce and chicken stock, heat while stirring until it is simmering. Serve hot with rice.