Melt butter in a large stock pot over medium heat.
Add onions and garlic, season with salt and pepper and cook until onions are soft and mixture is fragrant.
Add cubed squash, dried thyme and nutmeg and continue to cook, stirring frequently, for about 10 minutes.
Pour in the chicken stock and bring to a boil.
Reduce heat to medium-high and allow to vigorously simmer for about another 10 minutes or until squash is soft when pierced with a fork.
Remove from the heat and either use an immersion blender to puree, or carefully blend in batches in a conventional blender.
Return soup to pot and stir in coconut milk.
Season with salt and pepper to taste, garnish with roasted, salted chickpeas if desired, and serve.