Nas has become a scam not only because the Nas guys just copied and pasted the Nxt code and the client code but also because they and their marketing mislead people with false information to make people believe that Nxt dev team were behind the Nas project. Nxt dev team was never behind Nas.
 
one of their tricks was giving away lots of Nascoin to a guy who also was running Nxt nodes with nxtcrypto.org domain name. Then this guy set up Nas nodes with Nas.nxtcrypto.org which Nas guys used to mislead and show people that Nas was backed by Nxt team, especially in the Chinese market. For instance, with a picture of Nas.nxtcrpto.org, they wrote their slogan as - "NAS is from Nxt team, as nodes give you all the info". It totally was a lie and misleading.

Nxt team and core devs have claimed that nxtcrypto.org was owned by one individual person and not belong to and backed by Nxt team. It was pure an ordinary individual activity motivated by large Nascoins giveaway ant this person is not in Nxt core team.