Melt the butter in the Instant Pot on sauté setting. Leave it on sauté and pour in the chicken broth, add the garlic powder, salt, hot sauce, pepper, and mustard. Whisk to combine. Dump the dry pasta into the pot. Don't stir, but do move it around until all pasta is submerged.

Cook on high pressure for 5 minutes. Quick release pressure when cooking time is done.

Leave pot on keep warm setting and add 1/2 cup of milk. Feel free to add more milk, if needed. Add the cheeses in handfuls, stirring in between to help it melt evenly. Then add the cubes of cream cheese and stir until incorporated.

Serve warm.