Boil rice and cool. Cut chicken into small squares. Cut mushrooms into small pieces and onion into small squares. Beat egg in bowl. Heat oil in wok. Add onion and stir fry, adding mushrooms.
Continue stir fry adding chicken and peas. Add rice and stir fry or toss to mix in well. Make well in centre and add egg mixture. Stir, scramble and mix in thoroughly. Add salt, sugar, M.S.G., and soy sauce. Stir fry and serve on plate or bowl.