I'm looking into timelapse processing software and must say LRTimelapse looks very promissing. However, normally I use Nikon's (well, Google's nowedays Capture NX software instead of Lightroom. So I was wondering if I'm able to either use Capture NX or LRTimelapse 'standalone', or if I really need to get Lightroom as well?

You'll need the adobe engine for raw/image processing in order to user LRTimelapse. So Lightroom or Adobe Camera Raw is necessary.