Tinga de Pollo from Puebla - Chicken Stew

Puebla has been the site of the oldest and most respected recipes in Mexican Cooking, true classics, now we have an shortened version for our modern times but still good:
Tinga de Pollo.-
8 chicken thighs (or whole chicken in pieces)
1 tsp salt
1 tsp pepper
1 tsp garlic powder
8 ripe, whole Roma tomatoes
4 cups chicken stock
4 chipotle chiles (careful, HOT, so I would go easy, one at a time)
250 grms chorizo
1 white onion, sliced thin
6 red potatoes, diced
1 tsp cumin 1 tsp black pepper
1 tbls oregano
1 large avocado, peeled, pitted and thinly sliced
1 cup crumbled Mexican queso fresco or Cotija
Place chicken in pot and add water to cover. Add salt, pepper and garlic powder. Bring to a simmer over medium-high heat and cook until done. If possible, let the chicken cool in the water. When chicken is cool enough to handle, remove the skin and shred meat. Set aside. Heat pan over high heat and add the tomatoes (no oil). Blister and char the tomatoes all sides. Turn off heat and add chicken stock and chipotles. Allow to cool. Pour into a blender and puree until smooth. Set aside. Place the chorizo and onions in a pot and cook over medium heat. When the chorizo has released some oil, add the diced potatoes. Reduce heat to low and cook until the potatoes have browned and gotten a little tender. Add cumin, pepper, oregano, the shredded chicken and the pureed tomato mixture. Simmer for 10 minutes. Add salt to taste. To serve, scoop into deep bowls and top with avocado and cheese. Serve with corn tortillas and Mexican beer.