Prepare the fish by patting the white fish fillets dry with paper towels.

Make spice rub by combining chili powder, cumin, smoked paprika, garlic powder, onion powder, and cayenne pepper in a small bowl.

Generously sprinkle the spice mixture over both sides of each fish fillet.

Heat olive oil in a large skillet over medium-high heat until shimmering.

Cook the seasoned fish fillets in the skillet for about 3-4 minutes per side until golden brown.

Make lime crema by whisking together sour cream, mayonnaise, lime juice, lime zest, minced garlic, and cilantro until smooth.

Combine shredded cabbage, carrots, and red onion in a separate bowl.

Dress slaw with lime juice, olive oil, sugar, salt, and pepper, and toss until evenly coated.

Warm tortillas in a dry skillet over medium heat for about 30 seconds on each side.

Assemble tacos by layering slaw, a fish fillet, and lime crema on each tortilla.

Serve immediately, optionally garnishing with fresh lime wedges.