Place the diced pork into a large mixing bowl and toss with the salt and pepper to season evenly.
Heat a Dutch oven over medium-high heat coals and add the olive oil. Add the pork to the oven and sear to a golden brown on all sides. Using a slotted spoon, remove the pork from the oven to a plate.
Add the onions to the oven and cook until softened—about 3 minutes. Add the garlic and continue cooking for another 1 to 2 minutes, taking care to not let it brown.
Add the tomatoes, cumin, cilantro and oregano, and stir well. Add the roasted green chiles, chicken stock and browned pork to the oven and bring to a simmer.
Once simmering, cover the Dutch oven and add a layer of coals to the lid. Simmer, stirring occasionally—and adding a little water if needed, to keep the meat covered with liquid—roughly 2½ to 3 hours.
Remember to keep adding hot coals to the cooking area to maintain an even heat. When the pork is tender (Lambert likes his almost falling apart), add the diced potatoes and sprinkle the cornmeal into the pot while stirring. The cornmeal will thicken the stew slightly and give it a sweet corn flavor.
Cook until the potatoes are tender—about 15 to 20 minutes. Serve hot with plenty of warm corn tortillas.