Your diode setup on the trigger outputs is a bit strange, once an output is set high, there is no way to pull it back low.
If you want to protect the nano’s outputs from a short to a supply rail, you should put the schottky diodes on the other side of the resistor and have them connected to both rails.
Like in this post, replacing “analog input” by “digital output”
The way the diodes are setup now, if the power supply is capable of supplying a short circuit current of more than 1A, a short to the -12V rail will first blow the diode connected to GND and then apply about -11.7V through the 1K resistor to the nano’s pin which it might survive, but the diodes will have made no difference.