In a large pot, bring salted water to a boil. Add some oil and egg noodles, and boil the noodles for 8 minutes or until they get cooked. Drain and rinse the noodles under cool running water to prevent them from cooking further.
In a large saucepan, combine broth, salt, and poultry seasoning and bring to a boil. Add celery and onion, reduce the heat, cover, and simmer the broth for 15 minutes.
Mix cornstarch and water together in a small bowl until the cornstarch is completely dissolved.
Gradually add to soup, stirring constantly.
Stir in noodles and chicken, and heat for a few more minutes.