Pour stock into a large saucepan and place over medium-high heat. Add chicken, cover and simmer for 10 minutes, or until chicken is cooked through. Use a slotted spoon to remove chicken. Set aside to cool, then shred chicken.
Add noodles to stock and cook uncovered for 3 minutes, or until tender. Add shredded chicken, corn, spinach, soy sauce and shallots. Season to taste with salt and pepper.