Begin by preparing the squash. To do this, first cut the squash in half lengthwise. Scoop out the seeds and stringy membranes and cut the ends off. Stand the squash up on a flat end. With a sharp knife, remove the skin by carefully cutting it away. Once all the peel is removed, cut the squash into ½″ cubes.
In a large soup pot, heat oil over medium heat. Once hot, add the onions and sauté for about 5 minutes, stirring occasionally, until onions are translucent and fragrant. Add garlic, chipotle peppers, bell peppers, and butternut squash, stirring to combine. Mix the spices together and then add to the vegetables, stirring until they are well coated.
Once your vegetables are well coated, add the vegetable broth, beans, tomatoes, and maple syrup. Add the ingredients to the soup pot and stir together.
Bring to boil and then reduce heat to a low simmer. Cover and simmer for 20 minutes, stirring occasionally. Taste and adjust spices and seasonings. When the squash is tender your chili is done. Serve with cilantro and avocado.