Prepare the vegetables: Slice the carrots and celery, dice the onion, and mince the garlic.
Add everything: Place chicken in the crockpot and add vegetables, garlic, and chicken broth.
Season: Add Italian seasoning, bay leaf, salt, and black pepper.
Slow cook: Cover and cook on LOW for 6 to 7 hours or HIGH for 3 to 4 hours until the chicken is tender and cooked through.
Shred chicken: Remove the chicken, let it cool briefly, then shred it into bite-sized pieces.
Return chicken: Stir the shredded chicken back into the crockpot and adjust seasoning.
Add noodles: Turn to HIGH, add egg noodles, and cook covered for about 20 to 30 minutes until tender.
Finish: Remove the bay leaf, stir in parsley, add lemon juice if desired, and serve hot.