Into the crockpot goes the chicken, broth, black beans, corn, tomatoes, tomato soup, and taco seasoning. Give it a little stir, and then cover and cook on low for 8 hours.When you are almost ready to serve (1 hour or so before), remove the chicken and shred. Add it back to the soup.Whisk the masa into the warm water until you have a smooth slurry, and then whisk it into the soup in the crockpot. Continue to cook on low until you are ready to serve.