In a small bowl combine salt, cayenne powder (optional), chili powder, cumin, dried cilantro, pepper, and tequila lime seasoning (optional). Mix until well combined. Set aside.
In another small bowl combine Pico ingredients. Onion, cilantro, lime juice, salt and pepper. (Note for hotter Pico add minced chopped jalapeño)
In a large bowl place diced chicken. Add seasoning mix. Stir to combine.
Preheat a large skillet, over medium-high heat, add olive oil and half of butter (3 Tablespoons). Add diced seasoned chicken. Cook until juices run clear and meat reaches a temperature of 165° F. About 7–10 minutes. Remove cooked chicken from skillet and set aside.
In the same skillet over medium high heat, add remaining butter and a splash of vegetable oil. Add 2-3 corn tortillas. Lay them flat. Working quickly, place a hefty pinch, or two, of grated cheese down the center of each tortilla. Add 2–3 tablespoons of cooked chicken on top of the cheese.
Fold the tortilla in half. Press down with cooking spatula. Cook until bottom is lightly crisp and golden brown. Using tongs carefully flip tortilla over and cook the other side. Once cooked remove from skillet and place on a paper towel lined plate.
Finish taco by topping chicken and cheese with a sprinkle of onion-lime Pico, guacamole, and sour cream.