Prepare the slow cooker by drizzling about 1 tablespoon of oil into the bottom. Separate your frozen pieces from one another and lay the chicken on top of the oil. In a medium bowl, whisk together the remaining oil, balsamic vinegar, tomato paste, brown sugar, dried, basil, garlic powder, and salt. (or use 1 cup of your favorite store bought sauce)
Pour over the chicken. Cover the lid on the slow cooker and cook on low for 6 hours or until the chicken is fork tender, reaches 165 F. and can be shredded with 2 forks. (if it is tough to pull, it needs more time)
Remove the lid and stir the sauce. * You can additionally place a mound of shredded mozzarella cheese over each chicken breast. Re-cover until the cheese has melted before serving.
Video
Notes
You could use another sauce too, but would need 1 cup (minimum) to create enough steam to cook to tender. I have used a bottle of barbecue sauce or teriyaki sauce to do the same thing. Same cook time applies no matter what sauce you use.If you only wanted to use broth the same goes, use 1 cup water or broth.