Place tomato sauce, sugar, vinegar, Worcestershire, mustard and chilli in a saucepan over medium heat. Bring to a simmer and cook for 3-4 minutes until the sugar has dissolved and sauce is sticky.
Combine tomato, coriander, lime juice, avocado and onion in a bowl and season. Divide salsa among warm tortillas and top with lettuce and chicken. Serve with hot sauce, sour cream and lime wedges.