Aside from JS...
(Nirsofts)
BulkFileChanger.
Add your group of files (drag & drop or whatever) into BFC
F6 (Change File Time), in the Modified:
row, enable Add, then 2 seconds
Do it.
Note that 'Do it', does it, so make sure what you're wanting to do is what is will do.
IOW, test on a copied set of files, first, verifying expected results.
Also note that you can do 1 second, but depending, 1 second may (or may not) effect a change.
(As in I'm guessing "1 second" is... I'm not quit sure, but is taking the milliseconds into consideration, & adding "1", but then with rounding, it
may end up being the "same" rather then +1. In the end, that probably ? won't matter, except you might have a sequence like 1 2 4 instead of 1 2 3.)