In a large mixing bowl, whisk together lime juice, olive oil, minced garlic, cumin, chili powder, smoked paprika, oregano, salt, and pepper. Add chicken thighs and coat well. Marinate in the fridge for at least 30 minutes.

Preheat grill or skillet over medium-high heat. Cook marinated chicken thighs for 5–7 minutes per side until charred and cooked through (internal temperature should reach 165°F).

Remove chicken and let it rest for 5 minutes. Slice into thin strips.

Warm tortillas in a dry skillet for 20–30 seconds on each side until pliable and slightly charred.

Assemble tacos with chicken, chopped onion, cilantro, and a squeeze of lime. Add optional toppings if desired.