Saute the onions in the olive oil for 5 minutes. Add the garlic and cook over low heat for a further 2 minutes.
Add the tomatoes, Worcestershire sauce, Chilli garlic sauce, mustard, water and BBQ sauce.
Heat some olive oil in a frying pan. Season the brisket and seal on both sides.
Place the beef brisket fat side up into a slow cooker.
Add the sauce and place the lid of the slow cooker.
Cook for 5-6 hours or until the beef is tender.
Pull apart the beef with 2 forks while warm and keep warm.
Prepare the guacamole by blending together the avocado, lemon juice and MAGGI Sweet Chiili Sauce
To serve place corn chips into a bowl. Add the pulled beef, avocado guacamole, MAGGI Salsa Roja, sour cream and red capsicum. Garnish with fresh coriander or fresh basil.