Put half of stewed tomatoes in a blender and puree.
Add garlic and onion and blend.
Pour into labelled bag and add all ingredients EXCEPT chicken broth.
Remove air from bag and seal.
Put into the second bag and seal.
Freeze for up to three months.
When ready to use, thaw.
Pour all into a crockpot and add chicken broth, stir.
Cook on low for 8 hours.
Remove chicken and shred, then return to crockpot.
Serve with grated cheese, cilantro and tortilla chips.