Cook a batch of taco chicken in your Instant Pot.
Prep and cook taco shells, per the steps above.
Wash and chop the lettuce, tomatoes, and green onions.
Shred or grate both cheeses.
Layer ingredients in any order you want, but I prefer to add the chicken into the taco shell first, then the cheese (it gets all melty on the warm chicken), and go from there.
Add a layer of lettuce, a layer of tomatoes, green onions, and whatever else your heart desires.
Don't forget a dollop of sour cream (though I love adding a good layer of sour cream before I even add the chicken; that way I have sour cream in every single bite).