In a medium bowl, combine shrimp, taco seasoning mix and 2 tablespoons of lime juice; toss to coat.
Season with salt and pepper to taste. Take the skewers and thread 4 shrimp per skewer.
Heat a grill on medium heat. Place the shrimp skewers on the grill and cook until nicely charred, 1 or 2 minutes. Remove from the grill and set on a large platter.
To assemble, place a skewer of shrimp on a tortilla and remove the skewer to leave the shrimp lined up in a row. Top with shredded lettuce, chopped onion and diced tomatoes with chilies.