1. In a mixing bowl, combine olive oil, chili powder, cumin, and garlic powder. Coat the fish fillets with the mixture.
2. Heat a skillet over medium-high heat. Cook the fish for 3-4 minutes on each side until cooked through and flaky.
3. Warm the corn tortillas in a separate skillet or microwave.
4. Assemble the tacos by placing pieces of fish on each tortilla. Top with shredded cabbage, cilantro, and a squeeze of lime. Serve with sour cream on the side.