1. Drain pilchards from the hot sauce - set sauce aside. In another bowl, flake the pilchards with 2 tbsp of hot sauce with a fork.
2. Make tomato salsa by finely chopping the tomatoes and onions and mixing with a splash of oil, salt, and pepper.
3. In an ovenproof dish, layer the tortilla crisps, drizzles of hot sauce and cheese.
4. Place under the grill until the cheese has melted.
5. Top with the tomato salsa, flaked pilchards and avocado.
6. Dollop over spoonfuls of sour cream and serve hot.