In large pot, place oil, chicken base, onion, and spices. Saute until onions are soft and clear, about 5 minutes.

In another container, combine masa harina with 1 quart water. Stir until all lumps dissolve. Add to sauteed onions, bring to boil.

Once mixture starts to bubble, continue cooking 2-3 minutes, stirring constantly. This will eliminate any raw taste from the masa harina.

Add remaining 3 quarts water to the pot.

Add tomatoes; let mixture return to boil stirring occasionally.

Add cheese to soup. Cook stirring occasionally, until cheese melts.

Add chicken; heat through. Makes 1 1/2 gallons or 16-20 servings.