Prep: rinse and soak the dried beans for at least 2-3 hours and overnight at most.
Set your Instant Pot to the "saute" function, then push the "adjust" button to adjust the heat to the "more" setting.
Add pancetta and let it cook without stirring for about 2-3 minutes until the pancetta is browned, then stir with a spatula to brown it evenly on the other sides until the pancetta is crispy and the fat is largely rendered (i.e., liquid and not still white around the edges of the pancetta). Remove the pancetta with a slotted spoon.
If a lot of fat is remaining in the metal inner pot, turn off the Instant Pot and carefully lift the pot out and drain off the fat until there's only about 2 tablespoons of bacon fat left. Return the inner pot to the Instant Pot and turn the Instant Pot back on to the "saute" function again, making sure to hit the "adjust" button again to adjust the heat to low.
Add the onions and saute gently for 7-8 minutes until the onion is translucent and soft. Add the garlic and saute for 1 minute more, then pour in the beans, chopped tomatoes, chili powder, bay leaf and chicken stock. Turn the Instant Pot to the "bean" setting and cook.
When the Instant Pot is done cooking, let the pressure come down using the 10-minute natural release method (letting the Instant Pot switch to the "Keep Warm" setting and letting the timer count up to 10 minutes, then releasing the pressure).
Taste the soup and add at least 1 tablespoon of salt and 1 teaspoon of pepper. Taste it again and add more seasoning to taste. Add the cilantro and serve immediately.
Recipe by Grits and Chopsticks at https://www.gritsandchopsticks.com/the-gravy-train/2018/04/instant-pot-pancetta-and-bean-soup.html