In a large fry pan with lid, saute carrots, celery, onion on medium/low for 8-10 minutes. Add the garlic, mushrooms and chicken and saute for a few more minutes. Add rinsed spinach on top and put the lid on. Turn to low and let the steam do its work.
Boil enough water (in a kettle) to cover the rice noodles. Pour over the noodles and cover, and let sit in its own pot for a minute or two. Drain when done. Add the noodles to the stir fry mix and mix together.