1. Liberally coat a large pot or Dutch oven with oil spray and warm water over medium-high heat. Add the onion and bell pepper and saute, stirring occasionally, for about 7 minutes, or until the onion softens. Add the garlic, stir everything together, and cook until fragrant, about 30 seconds.
2. Add the ground turkey or chicken. Use a spatula or large spoon to break up the meat as it cooks. Continue to cook about 6 to 7 minutes, until fully cooked.
3. Add the beans, diced tomatoes, tomato paste, pumpkin puree, broth, chili powder, cocoa powder, cinnamon (or pumpkin pie spice), cumin, black pepper, and optional cayenne pepper, and stir. Reduce heat and simmer for 20 to 30 minutes, stirring occasionally.
4. Right before serving, add the spinach and mix throughout. Enjoy the chili with desired toppings, such as avocado, nonfat plain Greek yogurt, cilantro, and salsa.