Can you please advise whether:

When transferring assets from an unincorporated association to an incorporated association (its the same business incorporating itself), if I can transfer them for Nil consideration? Or do I have to include nominal consideration in the agreement? What are the rules surrounding this?

It really doesn't make much of any difference.

Recitation of "for good and valuable consideration" (good meaning it's a gift; valuable meaning money, usually) may be required by the statutes governing sufficiency of real property deeds in wherever jurisdiction you are located, but probably not. Legal scriveners normally put that in to be safe (for historical reasons).

I would be more concerned with how an unincorporated association can own and transfer property. In theory, such an entity is basically a partnership, so it might be necessary that all members sign. I suggest you run this by an attorney in your jurisdiction, to avoid any problems in the future.