administration tool for IPv4 packet filtering and NAT
-X, --delete-chain [chain]
       Delete  the  optional user-defined chain specified.  There must be no references to the chain.  If
       there are, you must delete or replace the referring rules before the chain can  be  deleted.   The
       chain  must  be  empty,  i.e.  not contain any rules.  If no argument is given, it will attempt to
       delete every non-builtin chain in the table.
source manpages: iptables