Place chicken in a saucepan over medium heat with enough water to cover by 1 inch (3 cm).
2. Step
Add the smashed garlic and cloves. Simmer until the chicken is cooked through, 12-15 minutes.
3. Step
Remove the chicken from the pot, cool slightly, then shred with two forks.
4. Step
Place a cast-iron skillet over medium-high heat, until smoking.
5. Step
Add the tomatoes and roll slowly around until blackened on all sides, about 6 minutes.
6. Step
Add the seared tomatoes to a blender with chipotle peppers, chicken stock, cumin, and nutmeg. Blend until smooth.
7. Step
Heat the vegetable oil in a large pot over medium-high heat. Add the garlic, onions, and chorizo. Cook 2-3 minutes until the onions have softened and the chorizo has rendered a little fat.
8. Step
Add the lettuce and sauté 2-3 additional minutes, until softened.
9. Step
Add the tomato-chili mixture and cook for 3 minutes, stirring constantly to incorporate.
10. Step
Add the shredded chicken and bring mixture to a simmer. Simmer, uncovered, until most of the liquid has cooked off, about 10-15 minutes. Season with salt and pepper to taste.
