Heat the oil in a large skillet over medium heat. Add the tilapia and season with the chili powder, cumin, garlic powder, and onion powder. Cook until the fish is cooked through and lightly browned, about 5 minutes. Taste and adjust seasoning as desired.
Divide the fish evenly among the warmed tortillas. Top with avocado salsa (see below). Serve warm.
Avocado Salsa: In a medium bowl combine 2 diced avocados, 1 diced jalapeno pepper, 1/4 cup chopped red onion, 1 tablespoon lime juice, 1 tablespoon chopped fresh cilantro leaves, salt and pepper to taste.