Heat olive oil in a Dutch oven over medium-high. Add the onion and garlic and sauté, stirring occasionally, for 5 minutes. Add the butternut squash and cook another 2 minutes.
Mix together the spices, then sprinkle over the vegetables in the pot. Stir well to coat and cook for 1 minute, until fragrant. Add a small amount of the broth and scrape up any browned bits from the bottom of the pot.
Add the crushed and diced tomatoes, chipotle in adobo, and remaining broth and stir well. Bring to a boil, then reduce heat and simmer for 20 minutes.
Stir in the beans and continue simmering for 10 minutes, or until butternut squash is cooked through and tender.
Notes
For a thicker chili, stir in 2 tablespoons to ¼ cup of masa harina or cornmeal toward the end of cooking.
If you don't have Mexican oregano, swap in Italian oregano.