Easy Fish Tacos

Name: Easy Fish Tacos
Ingredients: 1 pound cod , tilapia, halibut, or other white fish filets; 2 to 3 teaspoons chili powder , enough to coat the fish; 1 teaspoon kosher salt; 1/2 cup sour cream; 1/4 cup mayonnaise; 3 to 4 tablespoons lime juice (from 2 limes); 1 teaspoon hot sauce , optional; 1/2 small head red cabbage , shredded (about 4 cups ); 12 taco-sized corn or flour tortillas; 1 avocado , sliced; 4 radishes , thinly sliced; 4 spring onions , thinly sliced; 1/3 cup roughly chopped cilantro