Add all the ingredients, except the chicken breast, to a blender. Blend on high powder until the tomatoes, onions, and all other ingredients have become a liquid and there are no large chunks.
2 Roma tomatoes, 1 White onion, 2 cloves Garlic, 1 cup Chicken broth, 3 Chipotle peppers in adobo, 1 teaspoon Dried oregano, ½ teaspoon Ground cumin, 2 tablespoon Caldo de tomate powder
Add the chicken breasts to the Instant Pot, and cover with the tomato mixture. Move the chicken around to ensure that there is some broth/sauce at the bottom of the pot. Cover with the lid, put the vent into the sealing position, and pressure cook on HI for 20 minutes.
3 Chicken breasts
Once the pressure cooking time has elapsed, allow the Instant Pot to naturally release for 10 minutes. If there is still any residual pressure in the pot, vent it until it is safe to open.
Remove the chicken breasts carefully, with tongs, and place on a plate or a cutting board. Put the Instant Pot on sauté mode on HI, to allow the broth to come to a boil and thicken.
Shred the chicken using two forks, and return to the broth in the Instant Pot. Turn the Instant Pot off once the broth has evaporated to your liking.