Add chicken breasts to the slow cooker, pour salsa/tomato sauce and balsamic vinegar on top. Cover and cook on low 6 hours or high 4 hours. (I really prefer cooking on low)
Shred chicken with a fork, or do like I do and shred by using a kitchen aid mixer...takes just 1 minute! (place cooled chicken in the mixer bowl and with the paddle attachment and turn it on to the low setting.
Let it turn until it is just shredded then remove the chicken. About 1 minute.
Add in all remaining sauce/juices from the cooking pot, stir to combine well.
Enjoy in lettuce wraps, salads, or with a cup of broccoli and cooked brown rice.
This chicken is WONDERFUL for food prep, and lasts 4-5 days refrigerated, or six weeks frozen.