Magic: the Gathering - Can Nantuko Monastery be destroyed?

The "It's still a land" is actually a detriment to it. As a creature, it can be destroyed and once destroyed, it's sent to the graveyard, just like all other dead creatures, land or not, but since it's a land, if your opponent changes it into a creature, it's still vunerable to something like Stone Rain, which destroys target land and sends it to the graveyard. Just because it's a land doesn't mean it doesn't go to the graveyard when destroyed, so whether land or creature, you kill it, it's gone. Combat Damage, Sudden Death, Wrath of God, Stone Rain, etc.