As nouns the difference between nudger and judger
is that nudger is one who, or that which, nudges while judger is one who, or that which, judges.
nudger
English
Noun
(
en noun)
One who, or that which, nudges.
*{{quote-news, year=2009, date=February 8, author=Jeff Sommer, title=When Humans Need a Nudge Toward Rationality, work=New York Times citation
, passage=In Mr. Thaler’s words, “Sunstein would be the
nudger in chief.” }}
judger
English
Noun
(
en noun)
One who, or that which, judges.
A judgmental person (contrasted with (perceiver) as a personality type).