Prep the chicken: Pat the chicken dry with paper towels. In a small bowl, mix chili powder, cumin, smoked paprika, garlic powder, onion powder, salt, black pepper, and red pepper flakes if using.
Rub the spice mix all over the chicken along with the lime zest and 1 teaspoon of the lime juice. Drizzle with olive oil to coat.
Make the quick crema: Stir sour cream (or yogurt) with lime juice, a pinch of salt, and a little chili powder or hot sauce. Set aside.
Heat the pan: Place a skillet over medium-high heat.
When hot, add a light drizzle of oil if your pan needs it.
Cook the chicken: Add the chicken and cook 4–6 minutes per side, depending on thickness, until nicely browned and the internal temperature reaches 165°F (74°C). If the outside is browning too fast, lower the heat to medium.
Rest and slice: Transfer chicken to a cutting board and let it rest for 3–5 minutes. Slice thinly or chop into small pieces.
Squeeze the remaining lime juice over the chicken and toss to coat. Taste and add a pinch more salt if needed.
Warm the tortillas: Heat tortillas directly over a low gas flame for 10–15 seconds per side, or in a dry skillet for 20–30 seconds per side until pliable and lightly charred. Wrap in a clean towel to keep warm.
Assemble the tacos: Add sliced chicken to each tortilla.
Top with cabbage, tomato or pico, onion, avocado, and cheese. Drizzle with the lime crema and sprinkle with cilantro. Serve with extra lime wedges.