In a large bowl, whisk together olive oil, lime juice, and taco seasoning. Add chicken thighs and coat thoroughly. Cover and marinate for 30 minutes at room temperature or up to 24 hours refrigerated.

Preheat the grill to medium-high heat. Remove chicken from the marinade and discard excess liquid.

Grill chicken for 4-6 minutes per side until cooked through and the internal temperature reaches 165°F. Let rest for a few minutes, then slice into strips.

Warm tortillas on the grill or in a dry skillet until pliable and lightly charred.

Assemble tacos by placing chicken strips on each tortilla, then topping with romaine lettuce, sliced red onion, jalapeño, chopped cilantro, and a drizzle of cilantro lime crema. Serve with lime wedges.