In a medium mixing bowl, mix the diced tomatoes, chicken broth, cumin, salt and pepper.
Place the chicken breasts in the bottom of a 4 qt or larger crock-pot.
Pour the liquid over the top of the chicken.
Cover and Cook on LOW for 4-5 hours.
Remove the chicken and shred with a fork.
Add the shredded chicken back to the crock-pot.
Serve using a slotted spoon to remove the chicken minus the liquid.
Serve with your favorite toppings.