How to get tethering Wifi Hotspot to work on your LG Nexus 5

https://productforums.google.com/d/msg/nexus/DRVyGHFAdjA/6Wiit9EBm4AJ

Vick Fisher's profile photo
6/25/15

Vick Fisher said:

OK- after a few more hours of trying, I found a solution, but it requires you to get the Android SDK on your PC.  If you’re not on Windows, don’t bother reading the rest of this.

That’s easily downloaded, though it’s over 200MB.  Once you install it, you’re ready to use the adb shell. Instructions for that here.  It’s really not hard even though it may sound like you need to be technical.
https://developer.android.com/sdk/installing/index.html?pkg=tools
You’ll also need to enable Android debugging on your phone.  This link shows how to do that.

http://www.greenbot.com/article/2457986/how-to-enable-developer-options-on-your-android-phone-or-tablet.html
Don’t worry, you don’t have to do any development.
After you make yourself a “developer” on your Android phone, you need to enable USB debugging.
Go to Settings -> Developer options -> and activate the “USB Debugging” toggle.
All you need to do then is:
Connect your phone to your computer with a USB cable.
Open a windows prompt to to the sdk\platform-tools folder inside the Android development kit folder.
Once iin sdk\platform-tools, type
.\adb shell.
This starts the Android shell (terminal where commands can be typed), which can work on your phone.
Once in the shell, type this:
settings put global tether_dun_required 0
Press return.  To confirm it worked, type this and press return:
settings get global tether_dun_required
 
It should print out a zero.
Then you can quit the android development kit.
Reboot your phone.
Hook up your phone to the computer and set up the USB tether hotspot.
It takes about a minute for mine to start up, but then hovering over the icon on the task bar shows: Network XX Internet access.
Hope that helps!