Preheat the oven to 400 degrees F. Coat the Anaheim chiles in 1 tablespoon of oil and roast in the oven until the skin blisters and the peppers soften, about 20 minutes. Remove the chiles from the oven and allow to cool. Once cooled, stem and seed the chiles, keeping the skin on (if there is some charring on the skin it's ok). Chop.
Heat the remaining oil in a large pot over medium-high heat. Add the pork and sprinkle with salt and pepper. Add the cumin and cook until the pork is golden brown all over, about 15 minutes, stirring as needed. Remove the pork with a slotted spoon and set aside. Lower the heat to medium. Add the chiles, onions, cilantro and garlic to the oil remaining in the pot. Sprinkle with salt and pepper. Saute the vegetables, scraping any brown bits from the bottom of the pot, until the onions are soft and golden, about 10 minutes. Stir in the flour and cook until the flour absorbs the excess liquid and is cooked through, about 3 more minutes. Return the browned pork to the pot along with the tomatillos and chicken stock. Bring to a boil, reduce to a simmer and cover with the lid. Cook until the pork is tender, about 45 minutes. Uncover and simmer until the liquid reduces slightly and the flavors concentrate, about 15 more minutes. Serve with tortilla chips and lime wedges.