Nothing but. [Welp. Nami may not be here any longer, but there's no question in Vivi's mind that Nojiko should stay with them, provided she hasn't already made other arrangements. Heck, even if she has...]

Nojiko-san? You haven't found a place to stay yet, have you? We've got plenty of room here, and I know it's what Nami-san would want. ...if you like, you could even stay in her old room.

[Hopefully that's not too abrupt an invitation.]