From memory, these are the "specifics": China was allegedly selling army supplies to Nepal prior to the declaration of civil war. There were a couple of trucks of munitions already bought and paid for, which were apparently delivered shortly after hostilities began. No more arms deals were done between the two countries after this according to every source. Even the arms deal itself is disputed; I spoke to a couple of Chinese communists about it (admittedly a few years back) and they'd never even heard of it. Could all be bs, there's really no evidence other than a couple of western press releases