Begin by chopping the onion and mincing the garlic, setting them aside for later.
In a skillet over medium heat, sauté the diced onion and minced garlic until they become translucent and fragrant, about 3-4 minutes.
Add the chili powder, cumin, smoked paprika, and cayenne pepper to the skillet, stirring for about 1 minute until the spices are fragrant and well-incorporated with the onions and garlic.
Transfer the spiced onion mixture into the slow cooker and pour in the pumpkin puree, drained diced tomatoes, vegetable broth, rinsed black beans, and corn kernels.
Stir everything together until the ingredients are evenly combined and the mixture looks vibrant orange with visible pieces of beans and corn.
Set the slow cooker to low and cover with the lid. Let it simmer for 4 hours, allowing all flavors to meld and the chili to thicken.
Once cooking is complete, lift the lid and give the chili a gentle stir to ensure everything is heated through and well combined.
Taste the chili and add salt and pepper as needed to balance the flavors.
Scoop the hearty pumpkin chili into bowls, where it features a thick, creamy consistency with chunks of beans, corn, and tender vegetables.
Optionally, garnish with fresh herbs or a drizzle of sour cream for extra richness before serving.
Enjoy this warm, comforting bowl of slow cooker pumpkin chili on a cool day, savoring the deep, smoky flavors and velvety texture.
