Prepare the ingredients as mentioned in the above ingredients section. (I used the baby bok choy without chopping it, but you could cut them if you wish.)
Marinate the chicken in the marinade sauce for 30 mins.
Heat the wok on the stove for 10 seconds on high heat. Add some cooking oil and spread the oil with the spatula. Then add the marinated chicken (with all sauce) and cook it for 3 to 5 mins on high heat. Stir it occasionally.
Reduce the heat to medium high and add all the vegetables. Stir them well. Cook it for 3 to 5 mins.
While you are cooking the chicken from step 3, boil some water in a saucepan (it takes 5 to 8 mins). Then add the udon noodles and boil them per manufacturer’s instructions. Drain the water. Set the noodles aside.
Add the udon noodles into the wok and mix them well with the rest of ingredients in the wok for 1 to 2 mins.