In a large pot (5-6 quarts), heat 1 tablespoon of oil over medium heat. Add diced onions and cook, stirring occasionally until lightly golden. Remove onions from pot and set aside on a plate.
Heat another tablespoon of oil in pot, and add the chicken pieces (you may need to do this in two batches). Cook, turning once until lightly golden, 8-10 minutes.
Return onions to pot with chicken, and add water, herbs, bay leaf, salt and pepper. Reduce heat and simmer for 20 minutes, partially covered.
Transfer the chicken to a plate to cool. Strain the broth through a fine-mesh strainer into a large bowl. Skim some fat from the top. (At this point you could refrigerate or even freeze the broth and finish the soup later).
Return the broth to the pot, and bring back to a simmer.
Add diced vegetables and simmer for 5 minutes so they are not fully tender. Add noodles and cook according to package directions. While vegetables and noodles cook, dice about half the chicken. Add chicken back to pot.
Ladle soup into serving bowls and sprinkle with chopped parsley if you wish.