Add oil, chicken pieces and Mexican rice in the inner pot of instant pot.
Then, add onions, tomatoes, cilantro and salt. Select “Sauté”.
Close the lid and press the press the “Manual” button.
Cook for about 6 minutes on HIGH pressure and release the pressure naturally through the steam vent.
Open the lid and remove the mixture in a bowl. Mix well.
Take one tortilla sheet and place a spoonful of chicken and rice mixture, black beans, avocado slices, shredded cheddar cheese and roll them tightly.
Cut them into small bites and serve.