In a zip bag or marinating bowl, combine the chipotle peppers in adobo sauce, 1 teaspoon cumin, and the juice of 1 lime. The marinade will be discarded afterward.
Marinate the chicken thighs for 15 to 20 minutes or overnight in the fridge.
Prep the toppings now or while the chicken cooks so that when it's ready, you can assemble your tacos. I like to mix the onion and cilantro in a bowl.
Cook:
Heat a large pan over medium-high heat. Once hot, add the olive oil and distribute it around to coat. Place the chicken thighs on the pan, allowing some room between them, and cook for about 7 minutes per side. You know chicken thighs are ready when the internal temperature measured with a meat thermometer reaches 175F.
You might need to cook these in batches. If so, keep the cooked thighs covered and warm on a plate.
While the chicken cooks, heat up the crunchy taco shells in a 325F oven by pulling them apart on a baking sheet. They just need 6 to 7 minutes until they're warm and crisp. The baking sheet should be positioned in the middle of the oven.
Remove the chicken thighs from the pan onto a cutting board. Slice the thighs diagonally and again into small pieces.
Assemble:
Fill a crispy taco shell with the juicy, cooked chicken thigh pieces, topped with the cilantro and onion, and served with a lime wedge. If you're into spicy, add jalapeños.