A nudge could also be a bit more of a "go on, take the next step" or "you first," or even "it's OK." A nudge can be subtle, it can be layered. So, here, we can encourage a reader to step forward to a new genre or a different author, to take a risk. We could be saying to the reader, tell me what YOU think first so we really get an honest reaction. Or we could even be saying to the reader, go ahead and stay with the reading easy books for a while. I understand: sometimes we just need to read comfortable texts.
A nudge, IMHO, is encouraging. Too much force and a nudge becomes a push. That is too aggressive, too much in the reading community. Pressure needs to be at a minimum.
I am careful about nudges having written the mother of all nudge books: READING LADDERS. I have to stop sometimes and say forcefully, "we do not always have to be sending readers up and up those steps." It is okay to pause on a rung and stay awhile. It is okay even to step down. When I am feeling overwhelmed, I often revert to reading a stack of picture books. I feel a sense of accomplishment when I do this (and if you see the book blog here: http://www.ls5385blog.blogspot.com you will see I have been reading a lot of picture books this year). And I know that if I read 10 picture books, I have read 320 pages. Reward.
So, nudge gently. Know when to tuck in the elbows and stop nudging.
Maybe next week we will pick on a new letter of the alphabet...