2) Simmer for 1 1/2 hours until the meat is fork tender and comes easily apart with a fork. If you need to add some more liquid during the cooking process, add more beef stock or water. Remove the pan from the heat and allow to cool to room temperature, about 20 minutes.
3) When cool, cover the pan with a lid and place into the refrigerator. Cool in the refrigerator for 1 to 3 hours. After it's cold, trim off any remaining fat on the meat, cut into 4 pieces across the grain and then shred using 2 forks.
4) Place the meat back into the liquid until ready to serve. Before adding the meat to the salad, drain off the liquid and discard.
5) For the vinaigrette, whisk all the ingredients together, adding the olive oil in a steady stream until incorporated.
6) To make the salad, toss the lettuce and vegetables with the vinaigrette, and top with meat. Add freshly made corn tortilla chips around side of bowl.