From what I remember Nuneaton Rugby originally owned all the land, including the stadium.
The boro sold Manor Park, and ground shared with Nuneaton Rugby at Liberty Way.
Nuneaton Boro then purchased the land from Nuneaton Rugby, but it looks like they may have only purchased the stadium. All the other land (In red on the map below), car park and training pitches, are still owned by Nuneaton Rugby with option of Nuneaton Rugby using the stadium/pitch for Competition matches.
So it seems when Nuneaton Boro was liquidated, they changed the terms of the contract.
However I could be wrong on some of the details.