Prep everything except for the garnish ingredients and add them to the slow cooker. I like to add the chicken last so I can give the soup a good stir prior to adding it.
Cook the soup on high for 3-4 hours or low for 6-8 hours (I cooked it on high for 4 hours).
Take the chicken out of the Crockpot and shred it using 2 forks. Add it back into the slow cooker. Chop the cilantro and stir it in. Season soup with salt & pepper as needed. Serve immediately. I like to serve with a squeeze of lime juice, but that's optional. Soup freezes well for up to 3 months.
Serves 6+ depending on how much people eat.
Soup is slightly spicy; if you're worried about heat, omit the chipotle peppers and just use the adobo sauce. If you want it more spicy, I suggest adding more adobo sauce and chipotle chili peppers.