Long term I don't think Nitrile will hold up to modern fuels.
My nitrile gloves swell & soften if they are wet with fuel for a long time.
This happens when removing silicon from places where it never should have been.
Would butyl be a better material considering all of the scrap solvents that end up in "fuel" which is not petrol, now days.
I will have these in nitrile as well as Fluorocarbon rubber(viton). BTW, Viton is a proprietory name rather than a class of rubber.
I'm certainly no rubber expert but I do know there are many grades of both types. What I'm gonna do is let a few o-rings sit in our lovely E10 gasoline for a few days and see what happens.