[joris de man]

Easiest way I can think of:

You need to make sure that you have a bit of extra length on your files (2 seconds)...alternatively they might already have that if they're regions.

*Important* The last file should also be able to be extended 2 seconds, otherwise this won't work.

What we're basically going to do is shuffle all the items by sizing them with a 2 second length.
So, if you drag all the files on the timeline after eachother (you can do this in one go, Nuendo will ask you to put them on different tracks or on the same track), you should then do the following:
-Set snap on
-Set ruler to time/seconds
-Set grid mode to shuffle

Now, if you extend your samples by 2 seconds, they will all be moved 2 seconds from eachother, as shuffle lets them basically piggyback on eachother, but now you're adding a 2 second space.
You can then select grid mode, and resize the 2 seconds back again, and voila, 2 second spaced samples.

But, what if your samples have been truncated, and you don't have the 2 second space?

Simple, select a plug-in (EQ, whatever, it doesn't matter). On the plug-in, click on the 'More' button below.
Here you'll find sliders for mix, and pre and post fade, as well as Tail length.
Here you can add the 2 seconds or more. If you want to ensure your audio isn't affected, set the wet mix to 0 and the dry to 100%.
Press process, and all the regions are processed and will have the 2 seconds added.

You can then follow the previous steps to space the parts.

If the processing changes the region names, you can select offline history *after* you've done your spacing and undo the plugin on a per region basis.
(afaik, if you select them all, you should be able to remove the offline process in one go).

Cheers,

Joe