In a large pot of salted water, bring the potatoes to a boil. Cook until tender, 12 to 15 minutes. Drain and return to the dry pot.
While the potatoes are working, in a medium saucepan, heat 1/2 tablespoon EVOO over medium-high heat. Add the bacon and cook for 3 minutes. Add the onion, celery and thyme and cook until softened, 5 minutes. Add the corn and bell pepper; season with salt, black pepper and hot sauce. Cook for 3 minutes. Add the flour and stir for 3 minutes. Add the chicken broth and milk and reduce slightly, 2 minutes.
Mash the sour cream and chives into the potatoes; season with salt and pepper. Cover to keep warm.
In a large nonstick skillet, heat the remaining 2 tablespoons EVOO over medium-high heat. Season the halibut with salt and pepper, add to the skillet and cook until golden, turning once, about 7 minutes total.
Serve the halibut with the corn gravy and potatoes; top with parsley.