Place the chicken and sliced onion in the bottom of your slow cooker.

In a small bowl, mix together the garlic, chipotle in adobo, tomatoes, and birria seasoning until well combined.

Pour the sauce mixture over the chicken, making sure it’s fully coated.

Cover and cook on low for 6 hours or high for 4, until the chicken is tender and easy to shred.

Once it’s done, remove the chicken from the slow cooker and shred it with two forks.

To build the tacos, heat a non-stick skillet over medium heat.

Dip a tortilla into the cooking liquid (yes, it’s messy—but so worth it), then lay it in the hot pan.

Add a scoop of shredded chicken, a handful of cheese, and any toppings you like.

Fold the tortilla in half, press gently, and flip to cook the other side until it’s crispy and golden.

Repeat with the rest of the tortillas, then serve hot with extra sauce on the side for dipping.