Heat the oil in the Instant Pot using the sauté function.
Add onions and sauté for a few minutes until fragrant, about 2-3 minutes, stirring often.
Add garlic and ground beef. Stir continuously and sauté for another 4-5 minutes while breaking up the meat.
Drain any grease from the meat and return ingredients to Instant Pot.
Add bell peppers, corn, diced tomatoes, diced green chiles, cumin, chili powder, paprika, brown sugar, Worcestershire sauce, soy sauce, and dijon mustard. Stir to combine
Add tomato sauce on top of ground beef mixture. Do not stir after adding tomato sauce.
Put lid on Instant Pot and set to sealing. Cook on high/manual for 5 minutes.
Allow Instant Pot to naturally release for 10 minutes, and then quick release any remaining pressure.
While instant pot is releasing, cut the rolls in half and toast buns in a large skillet - cut side down.
Spoon sloppy joe mix onto the bottom bun and them place top half over the meat. Serve immediately.