Heat olive oil in a large Dutch oven
or other heavy-bottomed pot over medium heat. Add the onion, pepper and cook, stirring occasionally, until softened, 4-5 minutes. Add the pumpkin, walnuts, and bulgur and stir to combine. Add the chili powder, cumin, oregano, 1 teaspoon salt, ½ teaspoon black pepper, tomatoes, canned pumpkin and vegetable broth. Bring to a boil then reduce to a simmer. Cover and cook 15 minutes.