Heat olive oil in a large pot over medium heat. Add onion, carrots, and celery. Cook for 5–7 minutes until softened. Stir in garlic and thyme, cooking 1 minute more until fragrant.
Pour in chicken broth and add bay leaf. Bring to a boil, then reduce heat to a gentle simmer.
Drop the cubed chicken into the simmering broth. Poach for 8–10 minutes, or until chicken is just cooked through (internal temperature of 165°F).
Stir in egg noodles and cook according to package directions (about 6–8 minutes) until al dente. Remove bay leaf.
Taste and adjust salt and pepper. Ladle into bowls, sprinkle with fresh parsley, and serve immediately.