Expired chicken noodle soup is safe to eat well past it's expiration date as long as the can of chicken noodle soup has remained sealed and there are no rust or other leakage signs on the chicken noodle soup can.
Chicken Noodle soup is usually good for 5 years to 10 years past it's expiration date as long as it remains sealed in the can.
The canning of the chicken noodle soup helps to preserve the chicken noodle soup so that it lasts longer.
Expiration dates on canned foods is just a general guideline as to the freshness and quality of the canned food and the foods in cans and even boxed food can still be safe to eat well past the expiration date.
Food bargain stores can sell cheap canned food and other foods past the expiration date because it's safe to eat those foods.
I buy expired food all the time and eat it and save money as well.