In large stock pot boil chicken in 6 cups water until done. Remove chicken and let cool.
In a seperate pan sautee onion and garlic in butter until translucent, set aside.
Use a gravey sperator to remove fat from broth created from boiling chicken. Return broth to stock pot, add sauteed onion and garlic, frozen corn, chopped green chillies, cummmin, mexican oregano, chillie powder, salt, and pepper. If necessary add water to cover corn. Bring to boil, reduce to simmer. Simmer 30 minutes covered stirring occassionally.
Place 1/3 of corn mixture in blender and blend until a creamy consistency, return to pot.
Remove bones and skin from chicken and break into small pieces and add to corn mixture.
Simmer for an additional 30 minutes.
Add half and half and heat trough. If necessary, soup can be thickened with corn starch mixed with water to desired consistency.
This is great served with a garnish of crushed corn chips and grated cheese.