A Grammar Question: "Nor" and "they are" -v- "is"

This is a silly one, but it is bugging me. British English if it matters......

I have a disclaimer at the front, and on the back cover of our new book. The lawyer wrote this:

Neither the author nor the publisher are connected to, or in any way affiliated with XX Limited.

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One of my (US) editorial chaps insists it should be:

Neither the author nor the publisher is connected to, or in any way affiliated with XX Limited.

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I argued. My basis was "He is" - "They are". Publisher and author is "they" being plural, so "are" works for me. He insists the use of "nor" makes it "is". I am never too sure when to use "nor" or "or" actually. So I cant argue that the use of "nor" makes the use of "is" obligatory in that sentence.

So I defer to the good folk here to put me right please. How should that sentence be worded?

I stand corrected. Thanks both.