Great recipe from my mother-in-law.
1 London Broil
1-2 T taco seasoning (varies depending on how big of a London Broil you have)
1/2 chopped onion (or use dried)
1 T vinegar
1 can chopped green chiles
Spray crockpot with Pam. Rub taco seasoning on all sides of london broil. Place in bottom of crockpot and add other ingredients. Add water until water level is about half-way up the meat (or so). Cook on high for 5-6 hours. Shred meat. Return to crock pot for 1-2 hours. Serve on warmed tortillas with lettuce, tomato and cheese (like a taco).