Prepare the chile sauce: In a small pot over high heat, bring the water to a boil. Remove it from the heat and add in the dried chiles. Cover and let the chiles soak for 10 minutes.
Carefully transfer the softened chiles and the hot water into a large blender. Add the salt, chili powder, ground cumin, garlic, and Mexican chocolate. Blend for 2-3 minutes until completely smooth. Set aside.
Prepare the pozole: Season all sides of the meat with the salt and black pepper.
Press the saute button on the Instant Pot. When hot, add 1 tablespoon of oil and 3 or 4 pieces of meat. Brown the meat on all sides, flipping every 60 seconds. When browned, transfer to a plate and set aside. Continue working in batches until all the meat is browned.
Transfer all the meat back into the Instant Pot and turn it off. Pour in the red chile sauce and scrape the bottom of the pot with a wooden spoon to loosen all the brown bits. Stir in the broth, hominy, and dried oregano and combine.
Close the lid of the Instant Pot and move the valve to the sealing position. Press the Manual or Pressure Cook button to high pressure, then adjust the +/- buttons until the time reads 45 minutes.
When finished cooking, carefully move the valve to the venting position and release the pressure. Remove the lid.
Shred the pork with a fork or spatula (it should fall apart very easily). Taste and season with more salt, if necessary.
Serve with toppings such as finely shredded cabbage, cilantro, lime juice, thinly sliced radishes, diced onions, and dried Mexican oregano.