Hiroshima-Nishi Airport (HIW) closed to scheduled airline service in 2012 and now operates as a heliport, so there is no passenger lounge here and none is coming back while the site remains in that role. Anyone searching for a Hiroshima-Nishi airport lounge is really asking about an airport that no longer handles fixed-wing commercial flights at all.
When Hiroshima-Nishi stopped serving airlines, its passenger functions, and any lounge question that goes with them, transferred to Hiroshima Airport (HIJ), the region's operating commercial gateway, located further from the city center than the old Nishi field was. Nishi sat close to downtown on the edge of the Ota River delta, a convenient in-town location that nonetheless could not match HIJ's longer runway and larger catchment once scheduled traffic consolidated there. HIJ is the airport that actually matters for anyone flying to or from Hiroshima today, and it is the place to direct any lounge research for the region.
Hiroshima Airport supports the kind of scheduled domestic and limited international service that can carry airline lounges and broader premium-access arrangements, though specific lounge names, hours, and membership acceptance should be confirmed directly with the airport or your airline rather than assumed, since this guide is not naming a specific facility without that level of certainty. What matters for trip planning is simply routing your expectations to HIJ rather than the closed Nishi site.
If you have old information referencing a lounge or amenity at Hiroshima-Nishi, treat it as outdated: the airport's conversion to heliport use in 2012 ended its role in commercial passenger travel entirely. For a current, accurate picture of lounge access serving Hiroshima, Hiroshima Airport (HIJ) is the airport to research, and checking its current lounge and access listings directly is the reliable way to plan a visit, rather than relying on anything tied to the old Nishi field.