Cook the bacon in a 5- to 6-quart Dutch oven or other heavy-duty pot over medium-high heat until browned and crisp, about 5 minutes. With a slotted spoon, transfer the bacon to a paper-towel-lined plate. Pour off and discard all but 2 Tbs. of the bacon fat.
Return the Dutch oven to medium-high heat and add the onion, half of the scallions, the celery, bell pepper, and thyme. Cook, stirring occasionally, until the vegetables begin to soften, about 5 minutes. Add the corn and cook until softened, about 2 minutes. Stir in the chipotle powder and cook for 30 seconds.
Add the half-and-half and chicken broth and bring to a boil. Add the grated potato, lower the heat to medium, and cook, covered, until the potato is cooked through, about 10 minutes. Season to taste with salt and transfer to 4 large soup bowls. Garnish with the reserved bacon and scallions, and the cheese, if using, and serve.