Melt butter in a large soup pot over medium heat.

Saute diced onions and chopped garlic until softened.

Add diced green chilies and diced tomatoes.

Simmer for about 10 minutes, stirring frequently.

Add peeled and cubed white potatoes and chicken stock.

Cook over medium heat until potatoes are tender, approximately 10-20 minutes.

Reduce heat to very low and add shredded cheese.

Simmer for about 30 minutes, stirring occasionally until cheese is melted and soup has thickened.

Season with salt to taste.

For best results, cool overnight before adding cheese, then heat and add cheese before serving.