In 4-5 quart slow cooker, toss chicken with half of the taco seasoning mix to coat evenly.
Top chicken with salsa. Stir until well combined. Cover; cook on low heat setting 4 to 4 1/2 hours, or until chicken is tender.
Remove chicken from slow cooker to bowl. Shred chicken with 2 forks. Retur shredded chicken to slow cooker along with remaining taco seasoning mix. Cover; cook on Low heat setting 30 minutes longer. Serve warm.