Put the whole chicken breasts in the slow cooker. Cover with salsa. Toss to coat chicken with salsa.
Put cover on slow cooker. Cook on high for 4 hours or on low for 6 to 8 hours. It’s done when chicken is easily shredded with a fork. Shred chicken. Put back in the slow cooker and toss with remaining salsa and juices left in the slow cooker.
Serve immediately or refrigerate up to 5 days in an airtight container.
Topping Ideas: Tomatoes, shredded lettuce, shredded Mexican cheese, scallions, cilantro.