Heat olive oil in a large saucepan, and saute onion and garlic until tender. Mix in broccoli, potato, and chicken broth. Bring to a boil, reduce heat, and simmer 15 minutes, until vegetables are tender.
With a hand mixer or in a blender, puree the mixture until smooth. Return to the saucepan, and reheat. Season with nutmeg, salt, and pepper.