Select the “Saute” button on the Instant Pot. Add the oil and heat it up until shimmering. To the instant pot, add the onion and cook, stirring occasionally, until softened, about 2 minutes.
Add the garlic, cumin, oregano, bay leaf, and the ½ teaspoon salt, and stir to combine.
Stir in the tomato purée, chipotle peppers, adobo sauce, and chicken broth; bring to a boil. Reduce the heat to low and simmer for 5 minutes.
Turn off saute. Season chicken breasts with salt and fresh ground black pepper. Add chicken breasts to the Instant Pot.
Secure the lid and Pressure Cook for 8 minutes. Then, allow 10 minutes of natural pressure release.
Open the Instant Pot, take the chicken out, and shred it using two forks or shredder claws. Stir the shredded chicken back in the pot and turn the Instant Pot to Saute mode. Cook for 5 minutes or until the sauce has thickened.
Taste for salt and adjust accordingly.
Serve in tacos, tostadas, salads, lettuce wraps, etc...