In a large pot over medium heat, heat the oil and brown the stew meat and the onions until onions are translucent; about 5 minutes. Pour in diced tomatoes, beef broth, and chili peppers. Stir in the garlic salt and cumin. Salt and pepper to taste. Bring to a boil, reduce heat and simmer for 1 hour. Add a little more beef broth or water if needed during simmering. Stir in cubed potatoes and simmer for an additional 30 minutes or until potatoes are tender. Serve over rice or with cornbread.