Place the chicken breasts in the slow cooker. In a bowl, stir together the BBQ sauce, peach preserves, lime juice, chili powder, garlic powder, and salt until smooth.
Pour the sauce mixture over the chicken and turn the pieces to coat evenly.
Cover and cook on low for 6 hours until the chicken shreds easily with two forks.
Shred the chicken directly in the slow cooker and stir it into the sauce to absorb the flavors.
In a separate bowl, combine the diced tomatoes, red onion, cilantro, jalapeño, and a pinch of salt to make the fresh salsa.
Warm the corn tortillas and fill each one with a scoop of the peach BBQ chicken followed by a spoonful of salsa.