Heat oil in a large soup pot over medium heat. Cook onion, carrots and celery for 5 minutes, then stir in garlic for 30 seconds.
Add chicken thighs, broth, bay leaf, thyme, salt and pepper. Bring to a gentle simmer and cook partly covered for 20 to 25 minutes until the chicken reaches 165°F.
Lift the chicken onto a plate and remove the bay leaf. Add egg noodles to the broth and simmer for 6 to 8 minutes, or the package time, until just tender.
Shred the chicken into bite-size pieces while the noodles cook, discarding any tough connective pieces.
Return the chicken to the pot and heat for 1 minute. Serve promptly so the noodles keep their shape.