The NVOCC means Non-Vessel Operating Common Carrier.

A Non vessel operating common carrier is a cargo consolidator who does not own any vessel, but acts as a carrier legally by accepting required responsibilities of a carrier who issues his own bill of lading (or airway bill), which is called House bill of lading under sea shipment and House airway bill under air shipment.

Activities between a NVOCC and a freight forwarder are similar to each other except some differences.
An NVOCC need not be an agent or partner of a freight forwarding company, where as a freight forwarding company can act as a partner or agent for an NVOCC.

 
Basically speaking, NVOCC acts a ‘carrier to shipper’ and ‘shipper to carrier’.

NVOCC can own and operate their own or leased containers.    NVOCC acts as a virtual carrier and accepts all liabilities of a carrier legally, in certain areas of operation.

Apart from the above, there are no major differences between a freight forwarder and NVOCC which is similar to each other.  You can click here to read more about