See Notes for sweet potato and chicken cooking instructions if you do not have an Instant Pot. You can also bake your sweet potatoes in the oven while you cook the chicken in the Instant Pot to save time if you like.
Cook your sweet potatoes: Prick sweet potatoes all over with a fork. Place steaming trivet in the bottom of Instant Pot pot then pour 1 1/2 cups water in the pot. Place sweet potatoes on trivet then secure the lid and cook on Manual, high pressure for 16 minutes. Quick release pressure and remove sweet potatoes from trivet. Set aside. Discard steaming water and rinse the cooking pot, making sure outside is very dry.
Make your shredded chicken: combine chicken breasts, taco seasoning, and can of tomatoes with green chiles (undrained) in the pot of an Instant Pot. Do not add water. Secure lid and cook on Manual, high pressure for 20 minutes. Quick release pressure and remove chicken breasts from the pot. Shred with two forks then return to pot. Stir on Sauté mode a few minutes until sauce is absorbed.
Meanwhile, make your sauce: combine all avocado-jalapeño sauce ingredients in the bowl of a food processor and process until smooth.
Make the guacamole: mash avocados and stir in avocado-jalapeño sauce.
To serve: with a knife, make a slit down the top of each sweet potato and press sweet potatoes end's toward the center to push open. Top with shredded chicken, guacamole, avocado-jalapeño sauce, salsa or more tomatoes with green chiles, and garnishes. Serve immediately.