* Fitch predicts 20% hit to Nigerian bank revenues this year * Central bank measures exacerbate lending, FX shortage woes * Economy faces COVID-19, oil price shock double whammy By Chijioke Ohuocha and Karin Strohecker ABUJA/LONDON, July 28 (Reuters) – Nigeria’s banks are expected to take a big hit to revenues and face rising borrowing costs this year as central bank measures to support the naira currency squeeze lenders already hit by fallout from coronavirus and the oil price shock, analysts say. Banks in Africa’s largest economy – a mainstay for equity and fixed income frontier market investors – have learned to navigate challenges in a country that has long struggled with dollar shortages and multiple exchange rates. But the prospect of anaemic growth, dwindling oil revenues, declining remittances and dollar shortages exacerbated by the central bank’s latest action aimed at curbing naira liquidity and currency speculation are putting […]