Still no 5.1 OTA update available for my N5. I'll give the sideloading another go tonight but I'm getting frustrated that I'm stuck in the middle.
Maybe you should try my approach:
Step 1: Stop faffing around with all this sideloading ****
Step 2: Go outside... enjoy life
Step 3: Wait for OTA notification and take pleasure in the surprise when it comes.
Trust me. It will make you a better person.