Press the Saute button on your Instant Pot, then melt the butter.
Once melted, add diced red onion, jalapeño, and tomatoes and cook until the red onions are mostly translucent.
Add the cumin, paprika, salt, and pepper next and mix everything together.
Place the cream cheese on top of the vegetables but do not stir, then cancel the Saute setting.
Put the lid on your Instant Pot and make sure the vent is pointed to Sealing.
Set it to Manual Mode or Pressure Cook at High Pressure for 1 minute. (It will cook in the time it takes to come to pressure.)
When the cooking cycle is finished, do a controlled release of the pressure to be sure that you don't spray cheese everywhere. You can do this by releasing the pressure in short spurts until you can confidently leave the vent open with only steam coming out.
Now stir everything together - the vegetables should be really soft and the cream cheese should be melted enough to stir.
Now add shredded cheddar cheese and stir until it is melted. (Bagged or pre-shredded cheese will be difficult to melt, so freshly grated is recommended.) If the cheese is difficult to melt, set the Instant Pot to Keep Warm mode to expedite the process.
Once the cheese is melted, add heavy cream until it is your desired thickness. (We like thick queso so I add around ½ a cup. To make the queso pourable and thin, add ¾ cup or more if desired.)
Allow queso to sit for a few minutes to cool, then serve with tortilla chips and enjoy! Garnish with jalapeños and cilantro if desired.