The CLI command used for packet capture on the ESXi Node is 'pktcap-uw'. This is a utility specifically designed for capturing packets on an ESXi host and is preferred over other commands such as 'debug' or 'tcpdump'. While 'tcpdump' is a well-known command used for packet capturing on many platforms, 'pktcap-uw' provides more advanced and relevant capabilities tailored for the ESXi environment.