For the stock: Add all ingredients to a large pot. Bring to a boil, skimming off the top. Remove the corn from the cob. Add the corn cobs to the pot of chicken and let cook together. Reduce to a simmer and cook for 1 hour.
Remove chicken pieces from stock and let cool while you finish. Strain out all of the solids from stock and set aside.
In the blender, add the poblano, tomatillos, cilantro and about 1 cup of stock. Blend on high until smooth, set aside.
In a separate large pot, preheat 1 tablespoon of olive oil to medium heat. Add the reserved diced onion, garlic and jalapeño. Season lightly with salt and pepper and saute for 5 minutes.
To the onion mix, add the blended tomatillo/poblano sauce. Cook for 6-7 minutes.
Skim off some of the excess fat from top of reserved chicken stock. Add 6 cups of stock to the simmering sauce in pot. Stir well to combine and cook for 20 minutes.
Remove meat from the bones and add it back to the soup. Also add oregano and all of corn. Taste for salt and cook for another 10-15 minutes. Serve and garnish!