Pour salsa verde into the slow cooker.
Add spices, salt, and pepper; stir to combine.
Place chicken breasts in the slow cooker and turn to coat in the salsa.
Cook on LOW for 4 to 5 hours, until chicken is tender and fully cooked.
Transfer chicken to a cutting board and shred with two forks.(Optional: Use a stand mixer or hand mixer for faster shredding.) Return shredded chicken to the slow cooker and stir to coat with salsa and juices.
Serve warm in tacos, burritos, rice bowls, or salads.