Place the chicken breasts, white beans, chicken broth, onion, garlic, Italian seasoning, sun-dried tomatoes, salt, and black pepper into the slow cooker.
Cover and cook on low for 6 to 7 hours or on high for 3 to 4 hours until the chicken is fully cooked and tender.
Remove the chicken from the slow cooker, shred it with two forks, and return it to the pot.
Stir in the heavy cream, baby spinach, and Parmesan cheese. Cover and cook for 10 more minutes on low until the spinach wilts and the soup is heated through.