Put chicken breasts in a 5-quart slow cooker; sprinkle with cumin and salt.

Pour salsa verde over chicken. Cover; cook on low 3 1/2 to 4 hours until thickest piece reaches 165°F.

Transfer chicken to a shallow bowl; shred into thick strands with two forks.

Skim excess cooker fat; return chicken and fold through salsa.

Cover on warm 10 minutes while heating tortillas in a dry skillet.

Fill tortillas with chicken, cabbage, and cotija. Serve with lime wedges.