Dice the chorizo, then add it to the instant pot along with the cooking oil. Press the Sauté button, then the Adjust button to select the "less" temperature setting. Sauté the chorizo in the oil, without a lid, until it becomes slightly crispy on the edges.
While the chorizo is sautéing, dice the onion and mince the garlic. Once the chorizo is crispy, add the onion and garlic and continue to sauté until the onions are soft and transparent.
Add the beans, bay leaves, and pepper to the pot and wait a moment to let the beans absorb some of the heat and prevent the broth from splattering when it hits the hot pot.
Add the broth to the pot, stir briefly to combine, then place the lid on the Instant Pot. Close the steam valve, press the Manual button, select high pressure (if not selected automatically), then press the + button to increase the time to 35 minutes.
Allow the beans to cook through the 35 minute cycle, then let the pressure release naturally (you'll know the pressure has released when the silver float valve has fallen back down and is no longer flush with the top of the lid).
Once the pressure has released, open the steam valve, and then remove the lid. Discard the bay leaf. Add the canned diced tomatoes with all their juices, then stir to combine.
Press the cancel button to cancel the "keep warm" function, then press the Sauté button and use the Adjust button to select the "normal" heat level. Let the mixture simmer, stirring often, until the beans are very tender and the liquid has thickened.
Serve the beans with tortillas, tortilla chips, or over a bowl of rice, and with optional toppings like cheese, cilantro, green onions, or finely diced red onion.
*I didn't have any low-sodium chicken broth so I used the regular Better Than Bouillon that I have on hand. It was quite salty so if you are using regular broth instead of low-sodium I suggest using 2 cups broth and 1 cup water.**I used fire roasted diced tomatoes, which were awesome in this recipe!