Heat oil in a large pot over medium heat. Brown chicken breasts for 4 to 5 minutes on each side. Shred and set aside.
To the pot add onions and garlic; saute for 2 minutes, or until onions are translucent. Pour in chicken broth.
In a medium bowl combine masa harina with 2 cups of water and whisk until well blended.
To the onions and garlic add the masa harina mixture, remaining water, enchilada sauce, cheese, salt, chili powder and cumin. Bring to a boil; add shredded chicken. Reduce heat to low and simmer 30 to 40 minutes, or until thickened.
