Slow Cooker:

1. Sauté: Bring a cast iron skillet to medium-high heat and add oil to coat the bottom of the pan. Add shallots and garlic. Sprinkle with salt and pepper and stir, while allowing them to cook, about 2 minutes.
2. Slow Cooker: Scrape shallots and garlic into crock pot. Add chicken breasts and pour salsa verde on top. Cover and cook on High for 3-4 hours or on Low for 6-8 hours.
3. Shred + Serve: Remove chicken and shred with forks. Return to slow cooker, toss and serve any way you want.

Instant Pot:

1. Sauté: Set to Sauté Function. Once hot, add oil and allow to coat the bottom of the pot. Add shallots and garlic and sprinkle with salt and pepper. Stir and allow to cook, about 1-2 minutes.
2. Chicken + Salsa: Turn off Sauté Function. Add chicken and then pour the salsa verde over top. Move the chicken around, so each piece is fully coated.
3. Cook: Seal the lid on top and then cook on High Pressure for 20 minutes. Naturally release pressure for 10 minutes and then manually release.
4. Shred + Serve: Remove chicken from the Instant Pot and set onto a plate or cutting board. Use forks to shred the chicken and then return it to the pot. Mix the shredded chicken back into the salsa verde mixture. Serve immediately or store in refrigerator in an airtight container for 3-5 days.