Combine the chicken thighs with all of the Taco Seasoning Marinade ingredients and let the chicken rest for 30 minutes. The meat should look evenly coated, and the marinade will cling to the surface instead of sliding off.

Heat the oil in a cast iron pan over medium heat, then place the chicken in and sear the first side for 4 to 5 minutes before turning and cooking the second side for another 4 to 5 minutes. The outside should deepen in color, and clear juices running down the side of the chicken show it is cooked through.

Cover the cooked chicken and let it rest for 10 minutes, then cool it slightly and shred or cut it into bite-sized pieces. After resting, the meat will feel juicier and shred more cleanly instead of spilling its juices right away.

Add the diced onion, tomato paste, and chipotle in adobo sauce to the same cast iron pan and cook for 1 minute. The mixture should smell smoky and savory, and the tomato paste should darken slightly as it cooks.

Pour in the chicken broth and stir to loosen the browned bits from the pan. You want a smooth, reddish sauce that looks glossy rather than watery.

Return the chicken to the skillet and toss it through the sauce, then simmer for 1 minute so everything comes together. The filling should look lightly coated and thick enough to cling to the meat without pooling in the pan.

Heat a second skillet, lightly grease it with oil, and lay down one tortilla before sprinkling on about 1 to 2 tablespoons of cheese and topping it with about 2 tablespoons of chicken filling. The cheese should begin to melt quickly, which helps the filling hold in place when you fold.

Fold the tortilla over with a spatula and press gently, then cook for about 2 to 3 minutes until the bottom is crisp and golden before flipping to finish the other side. Do not flip early, because the taco is ready only when the bottom cheese forms a golden-brown crust.

Continue shaping and crisping the remaining tacos in the same way. Keep the finished tacos warm and watch for an even golden shell with crisp edges and melted cheese inside.

Serve the tacos with pico de gallo, guacamole, and any other accompaniments you like. The best tacos stay crisp outside while the filling inside remains juicy and smoky.