Press the Sauté button on the Instant Pot®. Heat oil 30 seconds. Add onion and bell pepper to pot. Stir-fry 5 minutes until onions are translucent. Add beef and pork and cook for an additional 5 minutes, using a wooden spoon to chop and stir as the meat cooks.
Add chili powder, garlic powder, cumin, salt, tomatoes with juice, and chiles with juice to pot and stir to combine. Lock lid.
Press the Meat button and cook for default time of 35 minutes. When timer beeps, let pressure release naturally until float valve drops and then unlock lid. Stir in cream cheese until melted and evenly distributed.
Transfer chili mixture to a serving dish. Garnish with cheese, Roma tomatoes, and scallions. Serve warm with chips.