Colombian Chicken and Potato Soup

I'm sure a real Colombian person would shudder at my interpretation of this soup; I should really just call it chicken and potato soup but Colombian makes it sound more exotic and interesting. You can use leftover chicken from a roasted chicken or if you make your own chicken broth, use the chicken meat from there.

1 large white onion, chopped
1 T olive oil, veg oil or butter
1/2 t dried oregano
1 potato, shredded coarsely on a box grater
2 potatoes, peeled and diced
6 cups chicken broth
2 cups leftover roast chicken meat
1 cup corn (frozen is fine)
chopped cilantro
vegeta seasoning or chicken bouillon
salt and pepper to taste

accompaniments: 
diced avocado
capers, drained
limes

Saute the onion in the olive oil until softened, about 5 minutes. Add the chicken broth, oregano, 1 t salt, vegeta to taste, pepper and both the shredded potato and the cubed potato. Bring to a boil and cook for about 15 minutes; add the corn and cook another 5-10 minutes or so until the potatoes are very soft. Add the leftover chicken meat and the cilantro and just heat through for a couple of minutes. Serve with the avocado, capers and I like a little squeeze of lime in my soup. Very hearty and delicious.