1. Combine 1/4 cup flour, salt and pepper in resealable food storage bag. Add beef; shake to coat beef. Heat oil in large skillet over medium-high heat. Add beef and garlic. Brown beef on all sides. Place beef mixture into slow cooker. Add broth to skillet scraping up any browned bits. Pour broth mixture into slow cooker. Add chilies and oregano.
2. Cover; cook on LOW 7 to 8 hours. For thicker sauce, combine remaining 1 tablespoon flour and water in small bowl stirring until mixture is smooth. Stir mixture into slow cooker; mix well. Cover and cook until thickened.
3. Serve with rice and garnish with diced tomato, if desired.
Use two cans of chilies for a slightly hotter taste.