Toss bacon into heavy soup pot, add onions, carrots, celery and simmer over medium heat, stirring occasionally, until onions are soft and slightly golden - about 10 minutes. If you are skipping the bacon, sauté the above in a Tbsp of olive oil.
Add black beans, stock, nutmeg, black pepper and water. Simmer until beans are soft - 1-2 hours.
Add lime juice, corn and half of chopped cilantro.
Add chili to taste: add it slowly and taste until you reach desired heat. You can always make your soup more spicy, but once you overdo it, sorry you've got practice in tolerating extra heat.
Simmer all for another 10 minutes, top with remaining cilantro and enjoy warm.