Place the stainless steel pot inside the Instant Pot. Start by roughly chopping up the onions. Add to the Instant Pot. Trim the tough stems off of the shiitake mushrooms and thinly slice them. Add them to the Instant Pot.
Chop up some canned chipotle peppers. Add them to the Instant Pot.
Then add the dried black beans and corn to the Instant Pot.
Chop or crumble the tempeh and add it to the Instant Pot (skip this step if not using tempeh).
Pour in the vegetable broth. The add both cans of tomatoes. Do not stir.
Add the chili powder, garlic powder, cumin, and oregano.
Then put on the Instant Pot lid, close the pressure release valve and press "Pressure Cook" or "Manual" until it’s on "High" and press the "Pressure Level" button until it’s on "Normal" (see note 3). Press the +/- button until it says "00:30". The Instant Pot will say "On" for quite a while until it comes up to pressure, then will start counting down.
When the Instant Pot is done, allow it to naturally release by just leaving it alone for 20 minutes until it says "L00:20". Then open the pressure release valve, steering clear of the steam.
When the pressure has released and the float valve has dropped, open the lid. Add the salt, stir, and taste. Garnish with cheddar, sour cream, jalapeno slices, lime wedges, or whatever you like in chili! If freezing, see note 4.