Drizzle the olive oil in the bottom of the slow cooker. Place the boneless, skinless chicken thighs and sliced onions in the slow cooker.
Add the tomatoes, water, and all the spices. Stir. Place the cover on the slow cooker and cook on high for 4 hours, or low for 7-8 hours.
Use a slotted spoon to remove the chicken from the slow cooker. Garnish with the cherry tomatoes and fresh cilantro.
Serve in taco shells or over tortilla chips with your choice of toppings.
Notes
If you'd like to prepare this for the freezer, simply place all the ingredients aside from the toppings in a ziploc freezer bag.Seal and freeze - it should stay fresh in the freezer for up to three months.When you want to prepare this, let it thaw in the refrigerator overnight, then cook according to the instructions above.