Are you having wifi issues with your Nexus 5?   I initially had issues with mine but did some troubleshooting and found the issue fairly quickly so thought I'd share the solution.

1.  It finds the neighbour's routers but your router says "Not In Range".
2.  It connects no problem to every other router you meet, but yours is not working.

The problem was that the Nexus 5 won't work with channels set higher than 8.   Mine was set to 13.   As soon as I altered the router settings and changed it to 8, the Nexus 5 connected immediately and I've had no issues since.

Next thing to resolve is finding a channel <= 8 that isn't being used by the neighbours.  

If this isn't your issue, another option may be to set your Nexus 5 to use 2.4GHz only, not mixed mode.