To a large pot over medium heat, add bacon. Cook until crispy, about 8-10 minutes. Use a slotted spoon to carefully remove the bacon and set it on a paper towel-lined plate. Reserve 2 tablespoons of the bacon drippings in the pot, discarding the rest.
To the reserved bacon drippings, add the onion. Cook for 3-5 minutes, or until softened. Add the garlic and cook for 1 more minute.
Stir in the chicken broth, potatoes, salt, and pepper. Bring the mixture to a boil. Then, reduce heat and simmer for about 15 minutes, or until the potatoes are tender.
Stir in the chicken, cheese, heavy cream, and half of the bacon.
In a small bowl, whisk together the cornstarch and water to form a slurry. Slowly stir the slurry into the soup. Continue to cook over low heat, stirring occasionally, until the cheese is fully melted and the soup thickens slightly, 1-2 minutes.
Garnish the soup with reserved bacon and green onion. Serve hot.
Notes
This soup can be stored in the refrigerator for up to 3 days.
Reheat gently on the stove over low heat, adding a little water or broth if needed to thin it out.