Foundation Prep: Dice the yellow onion, mince the garlic cloves, and carefully peel and cube the butternut squash. Set each component aside.
Sauté Aromatics: Heat the canola oil in the Dutch oven over medium heat. Add the chopped onion and cook, stirring occasionally, until softened and translucent, about 6–7 minutes. Add the minced garlic and cook for one minute more until fragrant.
Bloom Spices: Stir the tomato paste, chili powder, cumin, smoked paprika, dried oregano, and chipotle powder into the onions and garlic. Cook for 60-90 seconds, stirring constantly, to toast the spices and develop a deep, complex flavor base.
Brown the Turkey: Add the ground turkey breast to the Dutch oven. Use a wooden spoon to break it into smaller pieces. Cook until the meat is fully browned and cooked through, approximately 7–8 minutes.
Assemble the Chili: Carefully transfer the entire contents of the Dutch oven into the insert of your slow cooker. Add the cubed butternut squash, rinsed black beans, crushed tomatoes, fire-roasted tomatoes, and chicken broth. Stir thoroughly to combine all ingredients.
Slow Simmer: Secure the lid on the slow cooker. Set the temperature to LOW for 7–9 hours or to HIGH for 4–5 hours. The chili is ready when the squash is fork-tender and the flavors have melded together beautifully.
Serve and Garnish: Give the finished chili a final stir. Ladle into warm bowls. Top with a dollop of Greek yogurt, a sprinkle of fresh green onions and pepitas, and serve with a lime wedge on the side. The acidity from the lime brightens all the flavors.