I'm no fan on Scottish independence, but I have to say, I think this is a massive over-statement.
The nuclear weapons issue is a thorny one and there are obvious questions as to what will happen to the British army/defence capabilities if and when Scotland becomes independent... but it hardly plays into the hands of the 'forces of darkness', or even makes the world a more dangerous place... it is likely, if not certain, that there will a very long period of transition from Scotland being armed to the teeth with nuclear weapons to not having any - indeed, it may not ever happen, whether or not Scotland becomes independent. But I seriously doubt that the British Isles will be any less well defended no matter what happens - Scotland may become independent, but that doesn't mean that England and Scotland cannot continue to cooperate, just on a different legal basis.
Scottish independence is small beer compared to other, far more pressing threats to global security - religious extremism, poverty, fascism/communism, population growth/demographic change, social/economic instability, climate change, rogue states and various power struggles between would-be imperialist nations, to name but a few. Compared to any of those issues, Scottish independence doesn't even register.
It is highly ironic that seeking to acquire nuclear weapons is considered to be completely unacceptable on the basis that it is a risk to global security, and yet we're trying to get rid of the bloody things and that is considered a risk to global security as well!