Place diced chicken in a bowl and mix in the oyster sauce, leave to one side for 20 minutes.
Place wok over a medium to high heat, add oil and fry onions until translucent, now add chicken and allow to brown then add your mushrooms and peanuts. Once mushrooms have softened and the chicken is cooked, remove from the heat.
Wash your rice in warm water, discard the water and repeat 2 to 3 times.
Add enough water to cover the rice so it sits about 2cm above the top of the rice. Place over heat and hard boil until the water has been absorbed. Pour over your Chicken mixture, place lid onto the rice, switch off heat and allow to steam for 15 minutes.
Give rice a good mix and serve with soy sauce.