Combine the diced potatoes, finely diced onion, chicken broth, cream of chicken soup, salt, and pepper in a crock pot. Cover and cook on low heat for 5 hours.
Dice the cream cheese into small pieces. Stir in the cream cheese and shredded cheddar cheese, then cover and continue cooking on low for another 20-30 minutes, until the cheese has completely melted.
Serve the soup warm with your choice of toppings such as more cheese, crispy bacon, or chopped chives. Enjoy!