Bring a large pot of water to a boil, salt it, add the pasta and cook to al dente. Drain and return to the pot. While the pasta is working, position a rack in the middle of the oven and preheat the broiler. Place a small bowl upside down in a large bowl. Stand each ear of corn on the small bowl and scrape down the kernels.
Heat a skillet over medium-high heat. Add a drizzle of EVOO and the bacon and cook until crisp. Using a slotted spoon, transfer the bacon to a paper-towel-lined plate.
Add the corn, potato and Old Bay to the bacon drippings in the skillet and brown for 5 minutes, stirring occasionally. Add the celery, chile pepper, bell pepper, onion and garlic; season with the thyme, salt and pepper. Cook, stirring occasionally, until softened, 8 to 10 minutes.
Meanwhile, melt the butter in a medium saucepan over medium heat. Whisk in the flour, then the milk; season with the mustard, cayenne, nutmeg, salt and pepper. Cook until the sauce coats a spoon thickly; lower the heat to low. Stir in the parmigiano-reggiano.
Add the corn-potato mixture and the white sauce to the pasta in the pot and stir together. Transfer to a casserole or serving dish, top with the cheddar and bacon and broil until brown and bubbly, 3 to 5 minutes. Serve immediately.