In a large Dutch oven or heavy-bottomed pot, cook the diced bacon over medium heat until crispy. Remove the bacon with a slotted spoon and set it aside, leaving the rendered fat in the pot.

Add the diced onion, celery, and carrots to the pot. Sauté in the bacon fat until softened, about 5-7 minutes. Add the minced garlic and cook for another minute until fragrant.

Sprinkle the flour over the vegetables and stir constantly for one minute to cook out the raw flour taste.

Slowly whisk in the chicken broth until smooth. Add the chicken breasts, diced potatoes, dried thyme, salt, and pepper. Bring to a simmer, then reduce the heat to low, cover, and cook for 15-20 minutes, or until potatoes are tender and the chicken is cooked.

Carefully remove the chicken breasts from the pot. Shred them using two forks, then return the shredded chicken to the chowder.

Stir in the heavy cream. Let the soup heat through gently for 5 minutes, but do not let it boil. Taste and adjust seasoning. Serve hot, garnished with the reserved crispy bacon.