The AD8336 is a low noise, single-ended, linear in dB, general-purpose variable gain amplifier, usable over a large range of supply voltages. It features...
Datasheet AD8336 on Analog.com
I would suggest to follow the schematic on the datasheet and connect NC pins to ground plane. Those pins have no internal connections and we usually ground it for additional thermal dissipation unless stated on the datasheet.