Preheat the oven to 400°F. While the oven is heating up, start on the chicken.
Use a heavy bottomed stock pot and add the water, chicken bouillon seasoning, oregano and chicken breast. Bring this to a simmer over medium high heat and cook the chicken for at least 20 minutes. After 20 minutes, turn the heat off and remove the chicken from the pot (leaving the water in the pot), and set it aside in a bowl to cool down.
While the chicken is cooking, start on the verde sauce. Rinse the tomatillos, poblanos, and jalapenos really well to remove any debris. Place them on a baking sheet that is lined with aluminum foil (optional for easy clean up).
Place the peeled onion and garlic on the baking sheet as well. Place it in the preheated oven and roast them for 7 minutes, take the baking sheet out and use tongs to flip the peppers, onion, and garlic over. Put it back in the oven and cook for another 7 minutes. Remove the baking sheet from the oven and set it aside for the vegetables to cool down.
Open the two cans of hominy and pour them in a strainer to drain the liquid from the cans. Run cool water over the hominy to rinse it off thoroughly. Once it is rinsed well, add the hominy directly into the pot that the chicken cooked in.
Turn the heat on medium and allow the hominy to simmer while you prepare the sauce and the chicken.
Begin shredding the chicken by pulling it apart with your fingers, or by using two forks to shred it. Once the chicken is shredded, gently add it back into the stock pot with the pozole. Use a wooden spoon to mix it up. Cover and let it simmer while you prepare the sauce.
Once the peppers have cooled down to touch, gently peel off the outer layer of the skin by pulling it off with your fingers. Remove the stems and seeds from the peppers as well.
Place the roasted peppers, tomatillos, onions, garlic, cilantro, spinach, oregano, and cumin into a blender. Add about ½ cup of the liquid from the stock pot, directly into the blender. Blend on high for 2 minutes.
Use a fine mesh strainer to strain the pozole verde sauce directly into the stockpot with the chicken and hominy. This step is important to get a smooth soup without any extra seeds from the vegetables.
Use a spoon to mix the soup up really well. Place a lid on the pot and allow it to simmer for 20 minutes over medium heat. Use a mesh spoon or wooden spoon to remove any foam that has floated to the top of the soup.
Taste and adjust the salt and pepper as needed. Serve in a bowl with your favorite toppings, and ENJOY!