Heat 2 tablespoons of oil in a cast iron pot and add the chicken thighs.
Cook them for 2 minutes per side or until browned.
Add the chili powder, cumin and water.
Add salt to taste.
Bring the mixture to a simmer.
Cover and cook for an hour or until you can shred the chicken with 2 forks.
Shred all the chicken then put it back in the cooking liquid.
At this point you may refrigerate the chicken for 3 days before using, if you want.
Microwave the tortillas for 30 seconds or until soft.
Divide the chicken mixture between the tortillas.
Top with avocado slices and cilantro.
Serve right away with sour cream.
