Place the chicken breasts into the bottom of a slow cooker then pour tomatoes, salsa, black beans, pinto beans and corn over the chicken. Sprinkle taco seasoning, coriander, chilli powder and cumin over the mixture then stir to combine. Cover the cooker, set on Low then cook until chicken is very tender and the mixture has thickened, 8 to 10 hours.
For soup, leave all liquid in the cooker; for a thicker stew, remove some liquid if desired. Mix 1 or 2 tablespoons of liquid with cream cheese in a bowl, stir until smooth then mix the cream cheese into the cooker to make a creamy sauce. Continue to cook for 15 minutes, then serve.
Black beans (sometimes called turtle beans) and pinto beans can usually be found in organic food shops if your supermarket doesn't have them.