It is done all the time.
You can plumb or get your manifold plumbed for nitrous foggerr type system or you can use two plates. If using two plates understand that if you are using one system with one nitrous solenoid and one fuel solenoid shared with two plates that your horsepower increase will be half od what the system is for.
Example you have a 500 hp system and you share it on two plates, you will get a total of 250 hp or a little more, becuase of changes in flow restrictions etc.
If you use two systems combined on two plates using two ea solenoids for nitrous and for fuel, then you have full capability of the one plate system times two. It is not advisable to spray more than 500 shot through a plate system total.
Ed