Pre-heat the oven to 425 degrees
Place onion, peppers, tomatillo and garlic on a baking sheet. Drizzle with olive oil and sprinkle harissa over top. Use your hands to rub the oil and spice all over the peppers and onion.
Place peppers in the oven and roast for 25 minutes.
Place a large pan over medium high heat. Drizzle olive oil on the bottom. Sprinkle 1 tbsp of Mexican seasoning blend on each side of pork shoulder. When pan is hot add the pork shoulder and sear on one side. When a golden crust has formed on one side, flip the shoulder over and sear the other side.
When chilis are done roasting place in a food processor or blender and puree. Pour the green chili sauce over the pork shoulder. Add 2 cups of chicken broth and 1-2 tbsp of Mexican seasoning blend. Bring to a boil and then cover and let simmer on low for 2 hours.
When the pork shoulder is done cooking remove and shred with a fork. Serve the green chili pork with warm tortillas and extra sauce.
Enjoy!