In a large Dutch oven or heavy-bottomed pot, cook the chopped bacon over medium heat until crispy, about 8-10 minutes, then use a slotted spoon to transfer the bacon to a paper towel-lined plate, leaving the rendered fat in the pot.
Add the chopped onion and celery to the bacon fat and cook over medium heat, stirring occasionally, until the vegetables have softened, about 5-7 minutes, then add the minced garlic and cook for 1 minute until fragrant.
Sprinkle the flour over the vegetables and stir constantly for 1 minute to form a paste-like roux that coats all the vegetables.
Slowly pour in the chicken broth while whisking constantly to prevent lumps, then add the diced potatoes, dried thyme, and bay leaf, bringing the mixture to a gentle boil before reducing the heat to maintain a simmer.
Simmer uncovered for 15-20 minutes, stirring occasionally, until the potatoes are tender enough to be easily pierced with a fork.
Stir in the frozen corn and heavy cream, then simmer for an additional 5 minutes until the corn is heated through and the chowder has thickened slightly.
Remove the bay leaf, then season with salt and pepper to taste, keeping in mind the bacon already adds saltiness.
Ladle the chowder into bowls and garnish with the reserved crispy bacon and fresh chives before serving.
