Heat oil, add the onions and sauté, after that add the garlic. Add the tomato until they're soft and add the potatoes, salt, pepper and oregano. Mix well.
Add the the water, chicken bullion and cilantro. Cover the pot with a lid and cook until the potatoes are cooked through. Add the chile strips, after 5 min add warm milk.
Add the cubed cheese and cook for about 5 minutes.
Remove the cilantro and taste for salt & pepper to see if it needs more.
Serve warm with tortillas and enjoy!