According to the current plan, nudity may be present in events that require all hearts in the Ego screen to be unlocked. Also, when the middle heart is unlocked and certain conditions have been met, it may become possible for the player to remove all of Lily's clothes.
Note that plans may always change, but the main intention is that people who like full nudity will encounter it, while people who prefer to not have full nudity will be able to clear the game without encountering it.