Heat oil in a large pot over medium heat. Add onion and bell pepper, and cook, stirring frequently, until soft, about 5 minutes. Add garlic and cook, stirring, 1 minute. Stir in beans, broth, tomatoes, green chiles, chili powder, chipotle chile powder, and oregano. Simmer, covered, 10 minutes. Uncover and cook 10 more minutes.
Cut squash in half lengthwise, scoop out and discard seeds, pierce with a fork a few times, and put in a microwave-safe dish with 1/4 inch water. Cover with plastic wrap; microwave on HIGH 8 minutes or until tender. Let cool; peel with a small sharp knife, and cut into 1/2-inch chunks. Stir squash into bean mixture; cook 5 minutes. Stir in salt. Serve warm.
Andrea's wine pick: The chiles, beans, and squash demand the earthy smokiness of a French red Rhone wine. Look for the magnificent 2004 vintage of La Vieille Ferme Côtes du Ventoux ($99).