In a large pot bring chicken, water, garlic, and onion to a boil and let simmer. Transfer the chicken breasts to a plate and once cool enough to handle, shred the meat.
Strain and transfer remaining ingredients to a blender along with the chopped cilantro, oregano, tomatillos, garlic, and jalapenos. Pulse until coarsely chopped, scraping down the sides. With blender on, add 1 cup of the cooking liquid and puree until smooth. Season the tomatillo purée with salt to taste. Add the tomatillo purée to a pan and cook over moderate heat, stirring occasionally, until the sauce turns a deep green.
First add the hominy and bring to a simmer over moderate heat. Then, add the green sauce into the large pot with the cooking liquid. Then add the shredded chicken, Knorr Pollo Seasoning, and Mexican oregano, if needed, and cook just until heated through. Serve the pozole in deep bowls, garnishing with the lettuce, radishes, onion, avocado, sour cream, tortilla chips, and lime wedges.