Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a shallow bowl, mix together the flour, cornmeal, paprika, cumin, garlic powder, salt, and black pepper.
Dip each fish fillet into the flour mixture, coating both sides generously. Place the coated fish onto the prepared baking sheet.
Bake the fish in the preheated oven for about 12-15 minutes, or until it's cooked through and flaky.
While the fish is baking, prepare the sauce by combining the mayonnaise, sour cream, and lime juice in a small bowl. Whisk until well combined.
Warm the tortillas in a dry skillet or microwave them until soft and pliable.
Assemble the tacos by placing a few pieces of baked fish onto each tortilla. Top with shredded cabbage or lettuce, diced tomatoes, fresh cilantro, and any other desired toppings.
Drizzle the sauce over the tacos and squeeze some lime juice on top.
Serve the fish tacos warm and enjoy!