Add the chicken broth, macaroni, chicken, butter, onion powder, Italian Seasoning, and salt into the Instant Pot insert without mixing. Make sure the pasta is submerged.
Place lid on the Instant Pot, turn the valve to sealing, select pressure cook / manual high pressure, set the timer for 4 minutes, and cook until done.
Allow for a Natural Pressure Release (NPR) of 5 minutes and then do a Quick Pressure Release (cover the vent as the liquid will spurt), then open the lid.
Check the liquid (as chicken sometimes releases a lot of liquid) and scoop some out if there is too much.
Quickly mix in the cheese, warm milk, and cream, stirring until melted.
Adjust seasonings as needed, add any toppings or mix-ins, and serve.
Notes
If you prefer, you can use reduced-sodium vegetable broth instead of just water.
Keep the time under pressure to 4 minutes, any longer than that you will probably end up with mushy pasta.
Use store-bought shredded or grated cheese to save some time on this meal.
You don't need two different types of cheese. Use one if that is what you have, or change out the kind of cheese to suit your taste.
Cooking time does not include the time it takes for the Instant Pot to come up to pressure, or for the pressure to release.
Store – Refrigerate for up to 3 days and freeze for up to 2 months.