Nightmare Market has performed an exit scam, frauding it's users and vendors. We highly recomend you to use EMPIRE MARKET instead.
Empire Market is a Multi-sig escrow market that was created in late 2018. But it's core team has been in the Dark Web Markets web since 2013, working on AlphaBay Market. Empire market is one of the biggest and most trusted deep web marketplace supporting Bitcoin (BTC), Litecoin (LTC) and Monero (XMR)