Green’s Dictionary of Slang

(US) extraordinary, formidable.

1875		M. Thompson Hoosier Mosaics 129: But I tell you that red haired sister o’ his’n is lightning. She’s what bosses the job all round that ole shanty.
1876		‘Dan de Quille’ Big Bonanza (1947) 287: My fighter must be a regular lightning striker.
1883		‘Mark Twain’ Life on the Mississippi (1914) 74: By the Shadow of Death, but he’s a lightning pilot!
1934		(con. 1858) E. Cunningham Triggernometry (1957) 20: Man! but he’s a lightning gunfighter. [Ibid.] 49: It seemed impossible that the quiet, fiddling, likeable Jackson could be this lightning gunfighter.