@ditol
It's not actually in NewPipe itself as #NewPipe is designed to never pass any information about the user to the services it is downloading the video from.

What I do is hit the share button, copy the URL, then open #Tusky (or your fediverse client of choice), go to the search field, paste in the video URL, and then reply like you're replying a toot.

If you close NewPipe and open the video again (your history makes this easy), it should load your reply as a comment.