Heat olive oil in a large pot over medium heat until shimmering.
Add diced onion to the pot and cook, stirring occasionally, until it becomes translucent and fragrant, about 5 minutes.
Stir in the minced garlic, cumin, smoked paprika, and chili powder, cooking for another minute until the spices are fragrant and the mixture is bubbling gently.
Add the cubed pumpkin to the pot and stir well to coat with the spices. Cook for 5 minutes, allowing the pumpkin to start softening and absorbing flavors.
Pour in the diced tomatoes with their juices and bring the mixture to a gentle simmer. Cover partially and cook for about 15 minutes, until the pumpkin is tender and breaking apart slightly.
Stir in the drained black beans and cook uncovered for an additional 10 minutes, allowing the chili to thicken and flavors to meld.
Taste and season with salt and pepper as needed, adjusting the flavor to your preference.
Scoop the hearty pumpkin black bean chili into bowls, and serve hot, garnished with fresh herbs if desired.