In a dutch oven saute the chopped onion in some oil..add cooked beef. Add the taco seasoning and cumin to bring out the flavor. Then add all the rest except the chicken broth. You want to add the chicken broth to consistency you prefer your soup to be.
If rotel is too spicy you can substitute a small can of chopped green chiles for it.
Serve with grated cheese and sour cream over Fritos.