I had facing same problem of bootloop it happenes once in nexus 5x please do below as per this link and you will assure get out of bootloop : https://youtu.be/Z7AmTsC4N2c please refer it

I had facing same problem of bootloop it happenes once in nexus 5x please do below as per this link and you will assure get out of bootloop : https://youtu.be/Z7AmTsC4N2c