Apparently, Nismo outsource their thermostat's production/design to an actual thermostat manufacturer.
I personally use the Tridon brand thermostat(Tridon also make hose clamps) and costs the same as a stock thermostat.
Quote
Tridon Australia now offers a High-Flow Thermostat to improve cooling
system performance. High-flow thermostats have a larger valve (Fig.l) and
allow approximately 30% more coolant to flow to the radiator than standard
type Thermostats. Using High Flow Thermostats eliminates any need for
using cooler temperature Thermostats as a temporary cure for overheating
problems as was done in the past. Using correct High Flow Thermostat at
correct temperatures specified by OEM manufacturers will not interfere with
the engine management system.
All High-Flow Thermostats are fitted with a jiggle pin that enables the system
pressure to be stabilised so that the valve opens easier. The jiggle pin also
allows air pockets to move past the Thermostat and the temperature to be
regulated more efficiently. Fitting High-Flow Thermostats will allow your
vehicle cooling system to operate more efficiently.