Preheat oven to 375º F. Line a baking sheet with foil. Mix 1 cup nonfat plain yogurt, 1 tsp tabasco, 1 tsp oregano, 1 tsp chili powder and 1/2 tsp garlic salt in a shallow dish. Pulse 4 cups cornflakes in a food processor until coarse crumbs form. Add 1 cup pecans and pulse pecans in the food processor until coarsely chopped. (Alternatively, place cornflakes in a sealable bag and crush with a rolling pin; chop nuts with a knife.) Dip rockfish fillet in the yogurt mixture, then dredge in the cornflake mixture, coating both sides. Transfer to the prepared baking sheet. Bake the rockfish for 25 minutes, or until it flakes easily with a fork. Serve immediately.