Preparation Heat oil in heavy large pot over medium-high heat. Add onions and cook until soft and beginning to brown, stirring often, about 8 minutes. Add garlic; stir 1 minute. Sprinkle chili powder and coriander over; stir 1 minute. Stir in tomatoes with juice, beans, chipotles, and oregano. Add 10 cups water. Bring to boil, reduce heat to low, cover with lid slightly ajar, and simmer until beans are tender, stirring occasionally, about 2 hours (time will vary depending on freshness of beans). Season to taste with coarse salt and freshly ground black pepper. DO AHEAD: Chili can be made up to 2 days ahead. Cool slightly. Refrigerate uncovered until cold, then cover and keep chilled. Rewarm chili before continuing. Stir squash and bulgur into chili. Simmer uncovered over medium-low heat until squash and bulgur are tender, about 30 minutes. Season to taste with salt and pepper. Divide chili among bowls. Serve with sour cream, cheese, red onion, cilantro, and pickled jalapeño rings.
Preparation Heat oil in heavy large pot over medium-high heat. Add onions and cook until soft and beginning to brown, stirring often, about 8 minutes. Add garlic; stir 1 minute. Sprinkle chili powder and coriander over; stir 1 minute. Stir in tomatoes with juice, beans, chipotles, and oregano. Add 10 cups water. Bring to boil, reduce heat to low, cover with lid slightly ajar, and simmer until beans are tender, stirring occasionally, about 2 hours (time will vary depending on freshness of beans). Season to taste with coarse salt and freshly ground black pepper. DO AHEAD: Chili can be made up to 2 days ahead. Cool slightly. Refrigerate uncovered until cold, then cover and keep chilled. Rewarm chili before continuing. Stir squash and bulgur into chili. Simmer uncovered over medium-low heat until squash and bulgur are tender, about 30 minutes. Season to taste with salt and pepper. Divide chili among bowls. Serve with sour cream, cheese, red onion, cilantro, and pickled jalapeño rings.