In a large pot, add the vegetable oil over medium-high heat.
Add the onions and sprinkle with kosher salt and sweat for about 5 minutes until the onions have softened. Add the water and broth and simmer for 10 minutes.
Puree the frozen corn and the very hot broth and onions to the jar of a blender and puree on high until the soup is very creamy and smooth. You will have to do this in batches.
Then transfer the soup back to the pot and gently bring the soup to a simmer.
Add the chicken and the green onions and mix together. Season to taste with kosher salt.
Dish up hot and serve garnished with fresh green onions.
