Now I haven't seperated a lens yet, but I assume it's like an S3 or S4, and the touch imput is built onto the lcd panel. That should mean a relatively cheap glass only replacement option should be doable.
Can anyone correct me if I'm wrong? I've got a broken N5 and a working N5, but I've had too much fun testing roms on the broken one to want to do the seperation yet, so maybe the stack up prevents a glass only replacement. But I've delaminated N4s, G2s, S3s, and S4s, and replaced just glass/digitizers only, so I know the difficult process for doing it, and that it should be possible.