The Japanese title (roughly "Because I'm Staying Overnight with my Relative's Child") has been most commonly updated or translated in fan circles as "Staying with My Relative's Child" or "Overnight with My Relative's Child."
Originally promoted under various working titles, the "updated" name for official release tracking is . shinseki no ko to o tomari dakara de na name updated
The Intimacy of Shared Space: An Analysis of “Shinseki no Ko to Otomari” The Japanese title (roughly "Because I'm Staying Overnight