Heat olive oil or butter in a skillet over medium heat, then add the diced onion, carrots, celery, and minced garlic, cooking for 5-7 minutes until the vegetables are softened and aromatic.
Place the chicken breasts in the slow cooker, then season them with salt, pepper, and Italian seasoning.
Add the sweated vegetables to the slow cooker, followed by the chicken broth and cream of chicken soup, stirring to combine.
Cover and cook on low for 6-7 hours or on high for 3-4 hours, until the chicken is tender and fully cooked.
Remove the chicken breasts from the slow cooker, shred them using two forks, and return the shredded chicken to the slow cooker.
Stir in the heavy cream and uncooked egg noodles, then cover and cook on high for an additional 20-30 minutes, or until the noodles are tender.
Sprinkle in the fresh parsley and stir to combine before serving.