In a small bowl, combine the cumin, dried oregano, smoked paprika, garlic powder, salt, and black pepper. Rub the spice mixture all over every surface of the pork shoulder chunks, pressing to adhere.

Set the Instant Pot to Sauté mode on high. Add the avocado oil and let it heat until shimmering, about 1–2 minutes. Working in batches to avoid crowding, sear the pork chunks on all sides until deeply golden brown, about 3–4 minutes per side. Remove seared pork and set aside. (Skip this step if pressed for time, but searing adds significant flavor.)

Add the chopped onion to the pot and sauté for 2–3 minutes until softened. Add the smashed garlic cloves and chipotle pepper with adobo sauce, and stir for 30 seconds until fragrant.

Pour in the orange juice, lime juice, and chicken broth. Use a wooden spoon to scrape up any browned bits from the bottom of the pot — this is flavor, don't skip it.

Return the seared pork to the pot, nestling it into the liquid. The liquid should come about one-third of the way up the pork — that's correct for pressure cooking. Seal the lid and set the valve to Sealing.

Cook on Manual / Pressure Cook at High Pressure for 60 minutes. Allow the pressure to natural release for 15 minutes, then carefully switch the valve to Venting to release any remaining pressure.

Remove the pork to a cutting board. Use two forks to shred the meat, discarding the bone and any large pieces of fat. Reserve ALL of the braising liquid from the pot — this is liquid gold.

Taste the shredded pork and adjust seasoning with salt and lime juice as needed. For immediate serving, see the crisping step below. For make-ahead/camp, combine the shredded pork with the reserved braising juices in an airtight container and refrigerate for up to 4 days.

Place a cast iron skillet over high heat (campfire coals, grill grate, or camp stove). Let it get very hot — 2 to 3 minutes. You want it screaming hot before the pork goes in.

Add a thin layer of oil to the skillet, then add the carnitas in a single layer, working in batches if needed. Do not stir. Let the pork sear undisturbed for 2–3 minutes until a dark, crispy crust forms on the bottom.

Pour 2–3 tablespoons of the reserved braising juices over the pork and let it sizzle and reduce for 30–60 seconds, then toss the pork to coat. Repeat searing and adding juices until the pork is as crispy as you like — deeply caramelized edges are the goal.

While the pork crisps, warm the corn tortillas directly over the flame or in a dry skillet until lightly charred and pliable.

Build your tacos: layer crispy carnitas onto warm tortillas. Top with pico de gallo, avocado, cotija, diced white onion, fresh cilantro, pickled red onions, and a big squeeze of fresh lime. Serve immediately.