Add the oil to a large Dutch oven or stockpot and heat over medium-high heat to warm.
Add the carrots, celery, onion, and sauté for about 7 minutes, or until vegetables begin to soften. Stir occasionally.
Add the garlic and sauté for another 1 to 2 minutes.
Add the chicken broth, bay leaves, thyme, oregano, pepper, and bring to a boil. Boil gently for about 5 minutes or until the vegetables are fork-tender. Note – If you like brothier soup, add additional broth, as much as an additional 64 ounces because as time passes the noodles will continue to absorb broth.
Add the egg noodles and boil the soup for about 10 minutes, or until noodles are soft and cooked through. At any time while making the soup, if the overall liquid level is lower than you like and you prefer more broth, adding a cup or two of water is okay. At the end you just need to adjust the salt level to taste.
Add the chicken, parsley, optional lemon juice (brightens up the flavor), and boil 1 to 2 minutes, or until chicken is warmed through.
Taste soup and add salt to taste. I added about 1 tablespoon but this will vary based on how salty the brand of chicken broth used is, how salty the rotisserie chicken is, and personal preference.
Make any necessary seasoning adjustments (i.e. more salt, pepper, herbs, etc.), remove the bay leaves, and serve immediately.
Soup will keep airtight in the fridge for 5 to 7 days or in the freezer for up to 6 months.