In the pressure cooker, place the pinto beans and 3 cups of water. Lock the lid in place, bring to HIGH pressure, and cook for 2 minutes. Release the pressure. Drain and rinse the beans under cold running water.
Heat 1 tablespoon of the olive in the cooker. Add the onion, chorizo, garlic, and chilies. Cook about 2 minutes.
Add the beans to the cooker with 3 cups chicken stock, chili powder, cumin, and the remaining 1 tablespoon of oil.
Lock the lid in place, bring to HIGH pressure, and cook for 8 minutes. When done, release the pressure.
Drain some of the cooking liquid if it's too watery for your taste and stir in the salt. If desired, mash a portion of the beans. Simmer over low heat and stir in the cheese until melted.
Serve with additional cheddar cheese and green onions if desired.