nudgenik
n. A person who believes in using indirect suggestions, positive reinforcement, and other aspects of behavioral science to encourage people to make better choices in their lives.
Examples
2013
But don’t worry. The nudgeniks intend to save us from ourselves. By enlisting the theories of behavioural economics, they say they can get us to act in our own best interest.
—Konrad Yakabuski, “The nudgeniks can’t save us from ourselves,” The Globe and Mail, August 24, 2013
2013
Now that Sunstein is gone, Maya Shankar is becoming the new face of nudgeniks…

A nudgenik can’t give people what they truly want. "He can only make like an old-fashioned paternalist," writes Leonard, "and give people what they should want."
—Kyle Smith, “Nudge off!,” The New York Post, August 11, 2013
2012 (earliest)
Nudgeniks would point to what they claim are already massive successes: trials to deal with unpaid fines using text messages rather than letters suggest there is a 15 per cent rise in responses. Follow up with a text warning that bailiffs are coming and the numbers jump to 30 per cent.
—Mic Wright, “Malcolm Gladwell is not home secretary,” The Kernel, July 12, 2012
Notes
This term comes from the 2008 book Nudge: Improving Decisions About Health, Wealth, and Happiness, by the economist Richard Thaler and the legal scholar Cass R. Sunstein. A nudge, in this context, is any non-coercive suggestion, hint, cue, positive example, or canny arrangement of options that not only makes it more likely that people will make better choices, but will also make them believe they're still making their own choices. The authors call it libertarian paternalism.

Don't confuse a nudgenik with a nudnik, a Yiddish term that refers to a nagging, pestering person, which has been used in English for about 100 years.