Place raisins into your blender jar, and cover with hot water while you get everything else ready.
Place pork in your Instant Pot.
In a microwave-safe bowl, combine oil, onions, garlic, salt, oregano, both chili powders, and canned chipotle chili, sauce from chili and cook it on high for 5-7 minutes, stirring once or twice.
Pour this along with and cider vinegar and soy sauce or fish sauce into your blender jar with the raisins, and purée until smooth.
Pour this mix onto your pork.
Use the 1/2 cup of water to wash out your blender jar and pour this into the pot as well. Add another 1/4 cup water if you need to.
Set your electric cooker on High Pressure for 20 minutes, and quickly release pressure when done.
If you have too much liquid, either set your pot on sauté for 5-10 minutes to let some of it evaporate, sprinkle with xanthum gum to thicken while sautéeing, or make a slurry by mixing the cornstarch and the water, and pour into the pot. Let it boil and thicken.