Former JPMorgan banker and Wall Street high-flyer Chirayu Rana has hired an attorney who has repped Epstein accusers and other major sexual harassment cases in his legal battle with the nation’s largest bank over claims Rana was forced to be a “sex slave.” Daniel Kaiser, partner at top NYC law firm Kaiser, Saurborn & Mair, is representing the 35-year-old money man — dubbed “John Doe” in court filings — who last week filed a bombshell lawsuit against JPMorgan executive director Lorna Hajdini replete with “fabricated” claims that she drugged and sexually assaulted him . The financial giant has vehemently denied the allegations, with a JPMorgan spokesperson telling The Post that the suit is entirely fabricated, and that an internal investigation turned up no evidence of his salacious claims, noting Rana “refused to participate and declined to provide facts” to support his assertions.…