In a large pot over medium heat, cook chicken breasts in oil until well browned on all sides. Remove and set aside.

Cook onion and garlic in remaining oil until onions are translucent. Pour in chicken broth.

In a bowl, whisk together masa harina and 2 cups water until well blended. Pour into pot with remaining 1 cup water, enchilada sauce, Cheddar, salt, chili powder and cumin. Bring to a boil.

Shred cooked chicken and add it to the pot. Reduce heat and simmer 30 to 40 minutes, until thickened.