Marinate the fish:
In a small bowl, mix olive oil, chili powder, cumin, smoked paprika, garlic powder, salt, pepper, and lime juice. Rub the mixture over the fish, ensuring it’s evenly coated. Let it marinate for 15 minutes.
Prepare the slaw:
In a medium bowl, combine shredded cabbage, cilantro, lime juice, olive oil, and salt. Toss well and set aside.
Make the sauce:
In a small bowl, whisk together mayonnaise, sour cream, lime juice, hot sauce (if using), and garlic powder. Adjust seasoning to taste and refrigerate until ready to serve.
Cook the fish:
Heat a skillet over medium heat and add a drizzle of olive oil. Cook the fish for 3–4 minutes per side, or until it flakes easily with a fork. Alternatively, bake the fish in a preheated oven at 375°F (190°C) for 12–15 minutes.
Warm the tortillas:
Heat the tortillas in a dry skillet or microwave until warm and pliable.
Assemble the tacos:
Break the cooked fish into chunks and divide it among the tortillas. Top with slaw, a drizzle of sauce, and optional avocado slices. Serve with lime wedges on the side.