Prepare the Pork:

1. Season: In a large bowl, season the pork chunks with salt and pepper.
2. Brown: Heat the vegetable oil in a large, heavy-bottomed pot or Dutch oven over medium-high heat. Add the pork chunks in batches, browning on all sides. Transfer the browned pork to a plate and set aside.

Cook the Carnitas:

1. Sauté Aromatics: In the same pot, add the chopped onion and cook until softened, about 5 minutes. Stir in the minced garlic and cook for another minute.
2. Combine Ingredients: Return the browned pork to the pot. Add the orange juice, chicken broth, oregano, cumin, smoked paprika, and bay leaf. Stir to combine.
3. Simmer: Bring to a simmer, then cover and reduce the heat to low. Cook for about 2.5 to 3 hours, or until the pork is tender and shreds easily with a fork. You can also cook this in a slow cooker on low for 6-8 hours.

Crisp the Carnitas:

1. Shred Pork: Once the pork is tender, remove it from the pot and shred it using two forks.
2. Reduce Liquid: Increase the heat to medium-high and continue to cook the remaining liquid until it is reduced and thickened.
3. Crisp Up: In a separate large skillet or under the broiler, heat a little oil and add the shredded pork. Cook, stirring occasionally, until the pork is crispy and caramelized, about 5-10 minutes. Alternatively, spread the shredded pork on a baking sheet and broil in the oven, tossing occasionally, until crispy.

Serve:

1. Assemble: Serve the crispy carnitas in warm tortillas with your choice of toppings like shredded lettuce, diced onions, fresh cilantro, and lime wedges.
2. Garnish: Add salsa or hot sauce for extra flavor.