Chassis or floating on nDAC?

Hello - I’m using an Oppo BDP105D transport, Chord Company Signature Super ARAY Digital Coax to the nDAC. From the nDAC im using Super Lumina DIN5-5 into the Supernait 3. Should my nDAC be set to Chassis or Floating?

Chassis. The Naim DAC coaxial digital inputs are via pulse transformers so are galvanically isolated.

Thank you ! Very much !