Melt the butter in a large pot or Dutch oven over medium heat. Add the onions, carrots, and celery. Cook, stirring every few minutes for about 5 to 6 minutes until the vegetables begin to soften.
Stir in the garlic, bay leaves, and thyme. Stir constantly for about 1 minute.
Pour in the chicken stock and bring to a low simmer. Taste and adjust with salt and pepper if needed.
Add the chicken thighs ensuring that they’re covered with the broth. Bring the soup back to a low simmer and partially cover the pot with a lid. Stir occasionally for about 20 minutes until the thighs are cooked.
If the broth seems low, add a bit more stock or water to the pot. Reduce the heat to medium-low.
Transfer the cooked chicken thighs to a plate. Stir the noodles into the soup and cook for about 6 to 10 minutes until done, depending on the type of noodles.
While the noodles cook, dice or shred the chicken. Place the chicken back into the pot and taste the soup again for seasoning, adding more salt and pepper if needed. Stir in the parsley and serve hot.