Refer to Notes for alternative sweet potato and chicken cooking instructions if you do not have an Instant Pot. Alternatively, bake sweet potatoes in the oven while cooking chicken in the Instant Pot to save time.
Prick sweet potatoes thoroughly with a fork. Place the steaming trivet in the bottom of the Instant Pot, then pour 1 1/2 cups water into the pot. Arrange sweet potatoes on the trivet, secure the lid, and cook on Manual, high pressure for 16 minutes. Quick release pressure and remove sweet potatoes from the trivet. Set them aside. Discard the steaming water, rinse the cooking pot, and ensure its exterior is very dry.
Combine chicken breasts, taco seasoning, and an undrained can of tomatoes with green chiles in the Instant Pot. Do not add water. Secure the lid and cook on Manual, high pressure for 20 minutes. Quick release pressure, remove chicken breasts from the pot, and shred them with two forks. Return the shredded chicken to the pot. Stir on Sauté mode for a few minutes until the sauce is absorbed.
Meanwhile, combine all avocado-jalapeño sauce ingredients in a food processor bowl and process until smooth.
Mash avocados and stir in the avocado-jalapeño sauce to make the guacamole.
To serve, make a slit down the top of each sweet potato with a knife and press the ends toward the center to open. Top with shredded chicken, guacamole, avocado-jalapeño sauce, salsa or additional tomatoes with green chiles, and garnishes. Serve immediately.
