Set a 6-qt Instant Pot® to the high saute setting. Heat olive oil; add onion, and cook, stirring frequently, until translucent, about 3-5 minutes.
Stir in garlic, chili powder, cumin and oregano until fragrant, about 1 minute.
Whisk in flour until lightly browned, about 1 minute.
Stir in chicken, chicken stock, beans, green chiles, 1/2 teaspoon salt and 1/4 teaspoon pepper until well combined. Select manual setting; adjust pressure to high, and set time for 12 minutes. When finished cooking, quick-release pressure according to manufacturer’s directions.
Remove chicken from the Instant Pot® and shred using two forks. Return chicken to the Instant Pot®.
Stir in sour cream and cilantro; season with salt and pepper, to taste.