Add chicken breasts, chicken broth, Mexican tomato sauce, salt, pepper, oregano, cumin, and cayenne pepper into slow cooker. Set to high.
Let cook for about 4 hours, then set Crock-Pot® to warm. With a fork, shred chicken and let sit for about 20 minutes. Serve with tongs to remove chicken from juice for tacos, burritos or nachos. Enjoy!