I purchased Google's officially sanctioned charger, figuring the Nexus 5 would be optimized for it. Looks like it has been discontinued:

https://store.google.com/product/nexus_wireless_charger

Are there better ones out there that don't have as much of an issue with placement? My blind assumption was the problem lies with the phone's limited charging area, not the charger (which I presumed was nearly the whole surface).