There are some who believe that the Minhag of
not learning on Nital Night is a Chasidishe Minhag.
The חות יאיר in his (ספר מקור חיים (או"ח
קנ"ה writes, not
to learn on Nita nightl is the Minhag of the מהר"ל מפראג.
(About 180 years before the בעל שם טוב)