01 - Combine olive oil, lime juice, cumin, paprika, garlic powder, salt, and pepper in a shallow bowl.
02 - Add fish fillets to the marinade, coating thoroughly. Let rest for 15 minutes.
03 - Preheat grill to medium-high heat. Lightly oil the grates to prevent sticking.
04 - Place fish on the grill and cook for 3-4 minutes per side until just cooked through and flaky. Remove and let rest briefly.
05 - While fish grills, mix sour cream, lime juice, chopped cilantro, salt, and pepper in a small bowl until smooth.
06 - Place tortillas on the grill for 30 seconds per side until pliable and lightly charred.
07 - Flake the grilled fish into large chunks using a fork.
08 - Layer cabbage, fish, tomatoes, avocado, cheese, and cilantro on each tortilla. Drizzle with sauce.
09 - Serve immediately accompanied by fresh lime wedges.