Add the chicken breasts, chicken broth, black beans, both cans of diced tomatoes with green chilies, corn, chili powder, cumin, oregano, salt, and pepper to the Instant Pot liner. Do not stir excessively.
Secure the lid and set the vent to Sealing.
Select Manual or Pressure Cook (High Pressure) for 10 minutes.
When the cooking cycle finishes, allow a Natural Pressure Release (NPR) for 10 minutes, then carefully move the valve to Venting to release any remaining pressure.
Open the lid. Remove the chicken breasts to a cutting board.
Use two forks to shred the chicken. Return the shredded chicken to the soup.