Turn a 6-quart slow cooker on low. Pour one jar of salsa verde in the bottom of the crock. Place chicken breasts in the salsa verde. Sprinkle 1/2 teaspoon salt over the top. Then pour the remaining jar of salsa verde over the chicken.
Cover and cook for 6-8 hours. (3-4 hours on high.) Once cooked through, remove the chicken from the crock.
Use two forks to shred the chicken. Stir the shredded chicken back into the salsa verde. Turn the slow cooker on warm until ready to serve.
INSTANT POT INSTRUCTIONS:
Place the chicken breasts n the Instant Pot, and pour the salsa verde over the top.
Lock the lid into place, and set on Pressure Cook High for 15 minutes.
Once the timer goes off, perform a Natural Release.