I don't understand their opinions on the Nydus Worm. I feel as though we were playing different games. I was easily able to stop any and all Nydus Worms with just Siege Tanks. But you have to be aware of the threat and deal with it. It's just like in Brood War where you can't leave areas of your base uncovered by Siege Tanks because a Reaver could be dropped at any time. So against Zerg all you need is a few Siege Tanks covering your entire plateau. And with Siege Tanks having a newfound range of something like 15, that only requires about four.
though i never played the game id imagine a few cannons in the back of your base should do the trick of keeping them out.