In a heavy bottom pot over medium heat, add olive.
Add diced onions, bell peppers (jalapeños if using), oregano and cumin and saute until soft and tender, about 3-4 minutes.
Add minced garlic and stir to cook for 1 minutes.
Add chili powder, paprika, brown sugar, great northern beans, and garbanzo beans and stir to combine.
Stir in the pumpkin, tomatoes, and broth and bring it to a boil. Add more broth if you want a thinner chili.
Reduce the heat to a simmer and cover for 45 minutes to 1 hour.
Add diced turkey to just heat through.
Top with green onions, chives, cheese, jalapeños, avocado or sour cream, if desired.