Chili-Beef Soft Tacos

This is another mystery recipe...I ripped it out of a magazine long ago, but all identifying information was cut off. You can't go wrong with shredded beef tacos in my opinion and these definitely didn't disappoint! And they are so easy; just throw it in the crock pot in the morning and by evening you're ready to dig in.

-2 16-oz. jars mild or med tomato-based salsa (4 c.)
-2 T. cider vinegar
-5 t. chili powder
-1 1/2 lb. beef chuck pot roast
-12 corn tortillas
-sour cream, shredded lettuce, avocado (and cheese if you're like me)

-Spoon 1 c. salsa into small bowl; reserve. In slow cooker, combine remaining sals with vinegar and chili powder. Add beef, cover and turn heat to low. Cook until beef shreds easily with a fork, 10-12 hours. Shred meat, meat using 2 forks and spoon into serving bowl.
-Preheat oven to 300 degrees. Stack tortillas, wrap in foil and bake until warm, about 10 minutes. Serve with sour cream, lettuce, avocado and remaining salsa.