For the chili: Heat the oil in a heavy large pot over medium heat. Add the onion and sauté until almost tender, about 5 minutes. Add the bell peppers and sausage and sauté 5 minutes. Add the squash and sprinkle with salt and pepper. Sauté 2 minutes. Add 1½-2 tablespoons chili powder (depending on how spicy you like your chili) and cumin and stir until fragrant, about 1 minute. Add the drained beans, broth, tomatoes, and oregano. Bring to a boil. Adjust the heat so the chili simmers, cover partially and cook until the flavors blend and the squash is tender, about 20 minutes. Season to taste with salt and pepper.