In a large pot over medium heat, cook the chopped bacon until crispy. Remove the bacon with a slotted spoon and set it aside, leaving about 2 tablespoons of bacon fat in the pot.

Add the diced onion to the pot and sauté until soft, about 4 minutes. Stir in the minced garlic and cook for 1 minute more.

Add the diced potatoes and chicken broth. Bring to a boil, then reduce heat and simmer until the potatoes are tender, about 20 minutes.

Using a potato masher or immersion blender, partially mash the potatoes in the pot for a creamy texture, leaving some chunks.

Stir in the milk, half of the cheddar cheese, and half of the cooked bacon. Simmer for 5 minutes, then season with salt and black pepper to taste.

Ladle soup into bowls and top with the remaining cheddar cheese, bacon, sour cream, and chopped green onions. Serve hot.