I've read in a book From Flappers to Rappers: The Study of American Youth Slang two words used commonly within the same decade 1900-1910 meaning to hurry were "skin" and "niggle". I'm puzzled as to why these words would be selected and used to mean hurry: "Let's skin!" or "Let's niggle!". Any ideas?
After a superficial search, my guess is you may not find a logical answer to "why" other than someone decided to repurpose the word and it caught on. Sometimes, the meaning gradually changes because enough people simply choose to use (or "misuse") a word.
Your best bet is looking for the earliest instances of the terms with that usage (I haven't found any sources).
Niggle, in various dialects, has been given so many disparate definitions that asking "why" may not be the most illuminating question. Some definitions for niggle include cum, castrate, trot slowly, coax out, squeeze out or hand out slyly and possess carnally.
I was able to trace the "hurry" definition of niggle to "Dialect Notes, Volume 2" printed by the University of Alabama in 1900. I do not know their source, but it provides a time and perhaps geography (the source is not necessarily the American South).
I will update as I find more information. Perhaps an actual reason will appear.