Combine all of the ingredients in a freezer-quality bag.
Remove excess air, seal, and freeze.
Thaw in the fridge overnight.
Add water.
Put the soup in the slow cooker on low 6-8 hours or 3-4 hours on high.
Alternatively, you can use the Instant Pot, but don't add water. In that case, cook on high pressure for fifteen minutes and use a natural release.
Shred the chicken after it is cooked.