Place chicken, onion, carrots, leek, garlic, bay leaf and salt in a cooking pot. Cover the ingredients with water and boil until the meat is cooked through.
Place cooked chicken in a bowl and shredded it with two forks while is still hot.
Strain chicken stock and set aside.
Make the chipotle sauce.
In a pot place tomatoes and guajillo chilies. Add water and boil over medium heat until tomatoes are cooked through (about 10 minutes).
Allow tomatoes to slightly cool down, then place them in a blender with guajillo chilies, garlic, the spices mix, and chipotle chilies.
Pour in a cup of chicken stock, then blend until you’ll have a smooth sauce. Set aside.
Make the tinga
Heat the oil in a large cooking pan over medium heat. Add onions and cook, stirring constantly, until slightly soft and transparent (about 5 minutes).
Add shredded chicken and mix well.
Pour over the chipotle sauce, then add a cup of chicken stock. Season with salt and pepper.
Mix well and allow chicken tinga to cook for about 20 minutes while stirring from time to time until onions are cooked through and there’s almost not liquids in the pan.
To cook the meat for chicken tinga, you can use whatever cooking method is convenient for you, from instant/pressure pot, slow cooker pot, or a traditional stove. Just make sure the ingredients have enough liquid to be covered all the time.
You can also use a rotisserie chicken for this recipe, or what about Thanksgiving turkey leftovers? Those are perfect too!
Don't slice onions too thin because they will disintegrate when cooking with the sauce.
You can find canned chipotles en adobo chilies in Amazon and Mexican grocery stores. Otherwise, use 1 tablespoon of smoky paprika instead.
Adjust spiciness to your liking by adding more/less chipotle chilies.