2 lb. rump roast
1 c. chopped onion
1 pkg. taco seasoning mix
1 tbsp. oregano
1 tsp. garlic powder
1 (10 oz.) can diced green chilies
1 lb. can tomato sauce

Layer ingredients, meat first, in crock pot. Cook on low for 8-10 hours. Do not stir for first 5 hours. Shred meat after 7 hours. Serve on flour or corn tortillas. Top with sour cream, if desired.