Mexican Beef over Polenta

4 1/2-5 lb. chuck roast
1 (8 oz.) can diced green chili
1 (16 oz.) can stewed tomatoes
3 tbsp. chili powder
1 tsp. oregano
2 cloves garlic
Salt & cayenne pepper to taste
Prepared polenta, heated

In a large dutch oven, pour all ingredients except polenta over roast; cover pan. Place in oven at 325 degrees for 4 hours.

Shred beef, and spoon beef and sauce over polenta to serve.