Add the water, salsa, lime juice, fresh cilantro, salt, and pepper to your instant pot. Mix the ingredients together before adding your chicken breasts to the instant pot, then add the chicken breasts. Spread the chicken breasts out to ensure even cooking. 

Put the lid on your Instant Pot and ensure the seal is locked. Set your Instant Pot to cook on high pressure for 15 minutes. (If your chicken breasts are frozen, cook on high pressure for 20 minutes.)

The Instant Pot takes about 20 minutes to pressurize before starting the cooking time. Be sure to allow for this time in your cooking plan. 

After it is done cooking, allow the pressure to release naturally for about 10-12 minutes. You will know when the pressure is fully released when the float valve on the lid has dropped. You can also use the quick-release feature to release the pressure, but it may make your chicken a bit tougher than if you let the pressure release naturally.

Transfer the chicken breasts from the Instant Pot to a cutting board. Use a pair of forks or meat shredders to shred the chicken breasts. Return the shredded chicken to the Instant Pot to incorporate it with the juice. 

Serve this gluten-free Mexican shredded chicken in corn tortillas as tacos or over a bowl of cilantro lime rice.