Add the chopped pumpkin, garlic, onion, vegetable broth, coconut milk, cinnamon, nutmeg, sea salt, and black pepper to a large pot over high heat. Cover and let it boil.
When the pot begins to boil, turn down the heat to medium and allow the pot to simmer until the pumpkin is soft (about 20 minutes).
You can serve the soup as is, or you can blend the soup using an immersion blender or high-speed blender.