In a large pot, sauté the onions and garlic over medium heat until translucent, about 5 minutes.
Add the ground turkey (or beef) to the pot and cook until browned, about 7-10 minutes.
Stir in the chili powder, cumin, salt, and pepper, cooking for another minute to toast the spices.
Add in the bell pepper and cook for an additional 3-4 minutes until softened.
Incorporate the diced tomatoes, pumpkin purée, kidney beans, and broth, stirring to combine thoroughly.
Bring to a simmer, reduce heat, and cover the pot, allowing the chili to cook for about 30 minutes.
Taste and adjust seasoning as necessary, adding more salt, pepper, or chili powder to your preference.
Serve hot, topped with optional sour cream, cilantro, or cheese if desired.