The characters for Kawashiro mean "River Castle", while Nitori is in hiragana. There is a home furnishing chain store named Nitori in Japan, but it seems she has nothing to do with it.
Nitori is also a Latin word defined as either "brilliance, brightness, glow; splendor" or "perseverance; reliability", all fitting things to associate with such a brilliant engineer.
Her name might have originated from Ryunosuke Akutagawa's novel Kappa the second chapter of which begins with the sentence 「そのうちにやっと気がついてみると、僕は仰向けに倒れたまま、大勢の河童にとり囲まれていました。」(Sono uchi ni yatto kigatsuite miru to, boku wa aomuke ni taoreta mama, oozei no kappa ni tori kakomarete imashita.) "When at last I came 'round, I found myself lying on my back surrounded by a large number of kappas." — from the translation by Seiichi Shiojiri.
The Kappa in the series seem to be inspired by the Kappa in the above mentioned novel where they have their own civilization as opposed to their bloodthirsty nature in folklore.
Nitori's "Optical Camouflage" spell cards may refer to another aspect of kappas that Akutagawa writes about: "But what is most remarkable about kappas is that, unlike human beings, they change colors according to their surroundings."
Her backpack resembles a tortoise shell.
Nitori is the only playable partner in Subterranean Animism who never appeared in Scarlet Weather Rhapsody; all the rest of the partners did. However, according to an interview with ZUN, she was intended to appear in Touhou Hisoutensoku, but was scrapped due to time constraints.
As traditional depictions of kappa show a bald spot at the top of their heads, rumor has it that her hat is concealing that bald spot. However, ZUN discredited this rumor during a discussion on 2ch after Mountain of Faith was released.
Nitori's stage theme, The Gensokyo the Gods Loved, is similar to Remilia Scarlet's theme, Septette for the Dead Princess, most notably in the choruses.