Combine the Mexican oregano, chipotle powder, salt, and cumin in a small bowl. Rub it all over the meat. Heat 2-3 tbsp of oil in a skillet over medium-high heat and sear the meat on all sides until it is brown. Transfer the meat and pan juices to the slow cooker.
Wash the lemon and lime. Using a vegetable peeler, peel thin strips of the skin and add them to the slow cooker. Juice the lemon and lime, adding the juices to the slow cooker.
Add the chicken broth, pineapple juice, peeled and smashed garlic cloves, onion, and jalapeno to the slow cooker. Cook over high for 3-4 hours or until meat is fall-apart tender. Turn halfway through the cooking time.
Remove the meat from the slow cooker and set it aside until it is cool enough to handle.
Pull the pork into large shreds, picking out and discarding any fatty bits.
Heat 2 tbsp of oil in a large skillet over fairly high heat, but not smoking. Add the meat to the pan, letting it sit a few minutes to crisp up some of the edges.
Remove from the skillet, season it with salt and pepper, and serve in lettuce wraps, or serve with your favorite keto Mexican sides like avocado, lime crema (sour cream and lime juice), or low-carb tortillas.
I've not included the pineapple juice and veggies in the nutritional count because you're not consuming them.