A developers phone?

Im a android developer and im planning to buy a new phone for the scope of app development. My budget is 20k and my prefered choices are samsung galaxy note 5 and nexus 5. But my primary need is promising updates. I know nexus 5 is good in terms of update.but its a 2 yr old device...so I dnt know whether google will provide next update(which might be android N) for nexus 5.
If none of the above.Can you suggest me some other good options.