Heat a large heavy-bottomed pot over medium heat and add a splash of olive oil. Once shimmering, add the diced onion, carrots, and celery. Sauté for about 8 minutes, stirring occasionally, until the vegetables are tender and fragrant.
Pour in the chicken broth and bring to a gentle simmer. Add the cooked shredded chicken to the broth, stirring to combine. Let the mixture simmer for about 20 minutes, allowing the flavors to meld and the vegetables to soften further.
While the soup simmers, bring a separate pot of salted water to a boil. Cook the wide egg noodles until just al dente, about 7 minutes. Drain and set aside.
Taste the soup and adjust the seasoning with salt and pepper as needed. Add a squeeze of lemon juice for brightness, if desired, and stir in chopped fresh herbs for an extra fresh flavor.
Add the cooked noodles to the soup during the last 5 minutes of cooking, allowing them to soak up the flavorful broth and warm through.
Serve the hot soup in bowls, garnished with fresh parsley or thyme if using. Enjoy the comforting aroma and tender ingredients in every spoonful.