Mix together the dry noodles, stock, water, pepper, cumin, paprika, garlic powder, mustard, salt and green chilies in the Instant Pot.
Secure the lid and set the vent to the sealed position. Press "Pressure Cook." Adjust the pressure to "High Pressure." Press the "-/+" button until the time display reads 5 minutes.
Once the timer sounds, quick release the pressure. Mix pimento cheese into the noodles along with the cream cheese and half of the diced jalapeño.
Season with more salt and pepper to taste. Garnish with the remaining diced jalapeño.