Heat oil in a large saucepan over medium-high heat.
Add onion, bell pepper and garlic. Cook, stirring often, until the vegetables are just tender, about 5 minutes.
Add turkey and cook, stirring often, until browned, about 5 minutes.
Stir in tomatoes, beans, pumpkin, water, chili powder, cumin, smoked paprika, pepper and salt.
Bring to a boil over medium-high heat, stirring occasionally.
Reduce heat to low; cover and simmer, stirring occasionally, until the flavors meld, about 20 minutes, adding kale during the last 5 minutes of cooking.
Ladle into 4 bowls; top each with 1 tablespoon sour cream.
Garnish with cilantro, if desired.
