Heat the oil in a large pot over medium heat. Add the onion and a pinch of salt. Cook until translucent, about 3–4 minutes. Don’t rush it—sweaty onions are flavor-building level 1.
Add garlic, carrots, and celery. Sauté 2–3 minutes until fragrant. If your kitchen starts smelling like a soup joke coming to life, you’re doing it right.
Pour in the chicken stock. Bring to a gentle boil, then reduce to a simmer. Add thyme if you’re using it. Simmer 8–10 minutes until veggies soften but still have bite.
Stir in the shredded chicken and noodles. Cook according to noodle package instructions, usually 6–8 minutes. Taste for doneness: noodles should be tender, not mushy.
Season with salt and pepper. A quick taste test is worth a thousand guesses. If it needs color, add another pinch of salt and a splash of pepper.
Finish with a handful of chopped parsley. Ladle into bowls and serve hot. Optional: squeeze a little lemon for brightness if you’re into that.