Gwest77
I am not familiar with Moto, but to best of my recollection all of my past and current phones and tablets did not auto update major OS upgrades. They asked if i wanted to upload and then asked if i wanted to install. I just checked my current galaxy s2 and nexus 5 and there is no setting to turn on or off auto update.
If you are afraid of auto update when you turn on your particular phone, i can only suggest you take out sim card and go to a place with no wifi. You can turn on phone without risk of uploading anything and then go to settings to see if there is any way to turn off auto update on your particular phone. If there is not, i don't think there is anything else you can do. A phone with nougat is better than having no phone at all.
Or if you are so dead against using nougat, buy an obsolete phone which is no longer supported. For example my Nexus 5 will not get any other official support past marshmallow, but it is still a solid phone for me. Or if your phone is on nougat, you can always root and flash a custom rom including older version of android.