Turn Instant Pot to saute, spray with olive oil spray and add onions and garlic. Cook for 2 minutes.
Turn Instant Pot off and add the diced tomatoes, tomato sauce, taco seasoning and chicken broth. Stir together, then add the chicken.
Place the lid on the Instant Pot and lock it. Make sure the lever is set to seal. Press the manual button and set the time for 15 minutes.
Once the time is up let the pressure naturally release for 10 minutes.
Release the pressure and remove the lid. Remove chicken, shred it then add it back to the pot.
Add the corn and black beans. Turn Instant Pot to saute for 3 minutes to heat up corn and beans.