Prevent noodles from sticking when leftover in fridge
The cooking method for the noodles you're using says:


  
  Allow 1 block of noodles per person.
  Plunge them into a pan of boiling water and simmer for 4 minutes.
  Drain well and toss in a splash of soy sauce.
  
  
  When serving as part of a stir-fry: Rinse in cold water, drain, then add to the wok, tossing all ingredients together just before serving for a spectacular stir-fry with masses of flavour.


The first part of the method i.e. cooking the noodles separately is for when you want to use them plain.

The second paragraph of the method is what would be applicable in your situation. Cook your chicken/veg with the flavorings. Rinse the noodles in cold water, drain and then add to the pan mixing everything together just before serving.

When you cook the noodles with other ingredients without rinsing the noodles first, the starch washed off the noodles causes them to stick. So Yes, you're supposed to rinse them first.