When I modded my Wii I elected to not perform a NAND backup. Since I modded my Wii over a two years ago and no issues I think I'm relatively safe, but wouldn't mind the extra security of having it.
Reading through Mauifrog's Mod Any Wii it appears like a pretty straight forward process to create the NAND backup. (HBC-->bootmii-->hit power and reset a few times, etc.)
Would it be wise to do this, or has the window of opportunity passed since I've installed other things on my Wii since then (newer WAD files, Hermes 222/223, WiiFlow, etc.)
Thanks in advance for the knowledge
No it has not passed. Get that backup and keep it in a safe place (nand.bin, keys.bin and the bootmii folder).
alrighty then, thanks Krank
Do it. I do it every time I make a major change to my wii that I am happy with.
Yes you should, that way you can allways revert back to a safe restore point.