Daisy-chaining chassis can be the same thing as a multi-chassis system. If you have multiple DAQ devices, you could connect each DAQ device to its own SCXI 1000 chassis. If you only have one DAQ device, the SCXI-1000 chassis with the SCXI-1520 is full of modules, and you need additional channel count, you can purchase the SCXI-1346 which allows to connect multiple SCXI chassis to one DAQ device. Take a look at the document linked below for additional information. I hope this helps.
Can I Daisy Chain Multiple SCXI-1000 Chassis?
http://digital.ni.com/public.nsf/websearch/9C0A168318F47FB586256307006474B5?OpenDocument
Regards,
Todd D.