hello the thing is do you have any sugestions cause i have the enviremental linux thing on but it still wont open
I wish, I don't have a Chromebook, just a Linux computer. I wouldn't know how Linux mode on ChromeOS works. Actually now that I'm editing this, try dragging the executable for the game into the Linux terminal when it's open. That might work, if not, type in the executable directory into the terminal.
Actually, I have an easier solution. I did some testing and Five Nights at Fredrich's seems to run perfectly fine under Steam Linux Runtime 1.0. Install the ChromeOS version of Steam, add it as a non steam game, and make it run under Steam Linux Runtime 1.0 in compatibility. This should be an easier method if Linux mode is too much of a hassle to deal with on ChromeOS.