Difference between UNO and NANO when dealing with Hex files

[PantherPlayz]

I recently bought a T8 CNC engraver from Gearbest.
It uses a CNC-Shield and an UNO clone with GRBL 0.9 for Control.
The Uno was supplied with the HEX file for GRBL and a flashing tool.
Today i somehow managed to fry the UNO, and because i only use NANO's myself, i took some Jumper Wires and Pin-Matched the shield to the Board, then i used flashing Tool to upload the hex-files.
Problem: The NANO responds and can turn the Spindle on and off, but does not seem to interface with the Stepper drivers (Motors aren't moving).
I want to know if im doing something terribly wrong.
I always thought that UNO and NANO were the same thing (especially because my UNO uses an SMD-IC).
If anybody has any tipps on how to get my CNC shield to work or knows what im doing wrong i would be Graceful to hear from them.
Thanks in advance.

[Budvar10]

Both have same MCU so no difference from this point of view. The only difference is in USB/serial transceiver but with same functionality.

[DrAzzy]

Dollars to donuts you didn't wire it correctly, so something relevant to the servos isn't connected, or you wired power wrong (maybe you're inputing 5v on the RAW pin, so the board is runing at 3.something v, and at that point some of the connected devices won't recognize a HIGH?)