Preheat the oven to 450 °F
Line a baking sheet with foil and spray with nonstick spray
Cut the fish into one-inch chunks. A thicker piece of white fish, like cod loin, works well.
Put the egg whites and fish together in a bowl and stir to cover all the fish nuggets with egg white.
Mix the cornmeal, chili powder, garlic powder, oregano, pepper and salt together in a medium bowl or dish and dip the fish nuggets into the cornmeal mixture, turning to coat.
Transfer the fish nuggets to the baking sheet. Put the baking sheet in the oven and bake for 12-14 minutes, until the cornmeal coating turns golden brown. Use a spatula to flip the fish nuggets over around the 7-minute mark.
In a small bowl, whisk the dipping sauce ingredients together.