Im lookin to get into the nitro rc boat hobby, ive been into nitro rc cars for years so i have expirience in nitro, I live on the water so i thought i might as well try it, since the bay i live on is salt water, can i run nitro rc boats in salt water if i were to flush the engine every time i ran them?

Yes.
That seemed almost too simple.

Before heading out for the first day, do one simple item that will stop any headaches down the line. If the head bolts are open to the water in the water jacket, take all the head bolts out. Put a dap of anti-seize on the area of the exposed threads. Make sure the bottom of the screw has some blue loctite there. The reason for the anti-seize is that the salt won't be able to corode the metal screws. If this step is not done, it will be a pain in the rear to get them out. The loctite will make sure the screw does not back out on it's own.

I'd suggest flush everything, not just the motor, with water. Might want to spray a light mist of WD-40 where there is metal also.