Welcome to the forum and thank you for trying our products!
Your application looks very feasible based on the provided diagram. Note that the Nano-10 could make an outgoing connection via Modbus TCP to the DCS (push data) or the DCS could connect to each Nano-10s Modbus TCP server (poll for new data). If each Nano-10 is pushing data, then the DCS Modbus TCP server must be able to accept at least 8 simultaneous connections since it is possible for all 8 PLCs to contact the DCS at the same time. The Nano-10 is well suited to handle either scenario.
We also recommend adding a transient absorber diode (such as the 1N6282AG) to each PLC output in order to protect the outputs against inductive loads commonly associated with motor control. You can see a wiring example in chapter 1.5.3 of the Nano-10 user manual.