Prep the Chicken: Place 1½ pounds of chicken thighs on a plate or in a shallow dish. Sprinkle taco seasoning evenly over the chicken and massage it in with your hands to coat completely. Let the chicken rest and absorb the flavors for at least 15 minutes or up to 24 hours in the fridge.
Heat the Pan: Warm a large (12-inch) sauté pan over medium-high heat for about 3 minutes. Once hot, add 1 tablespoon of oil and swirl it around the pan until it shimmers.
Cook the Chicken: Gently place the chicken thighs into the pan, spacing them out so they’re not crowded. (You’ll likely need to cook in two batches.) Once the chicken is in the pan, leave it alone—don’t move or poke it—to ensure a nice sear. Lower the heat to medium.
Sear and Flip: Cook the chicken for 3-4 minutes. If it sticks when you try to flip it, it’s not ready yet. Once the chicken releases easily, use tongs to flip each piece. Add 1 tablespoon of butter to the pan and swirl to coat. Cook the other side for another 2 minutes or until golden brown and the internal temperature reads 160°F.
Rest and Repeat: Remove the chicken to a cutting board, cover loosely with foil, and repeat the process with any remaining chicken.
Shred the Chicken: Once the chicken has rested for a few minutes, slice it against the grain and shred it into smaller pieces. Transfer to a serving bowl, squeeze the juice of one lime over the top, and pour in any pan drippings for extra flavor.