Thinking this might help someone else out. When I bought my car in Jan the owner said, "You'll want to change the sandwich soon." He already the gasket in hand too. Well I put it on right away and it still leaked. Took it off and tightened to torque spec and it still leaked. The new gasket actually leaked more than the old one so I put it back on. I battled this and started reading other Nissan forums and found a great idea that worked for me. The sandwich has more than one ring on it. Well, the solution was to take off the gasket from the oil filter. It fits perfect on the inner ring of the sandwich plate. For good measure I left the other gasket in place. I now have no leak!

 

I've been fighting the same leak. Like you, installed new gasket, torqued down, but leak still randomly appears. I wondered about doubling up on the gasket. Had read elsewhere about using oil filter gasket (don't remember which specific filter #) in lieu of OEM gasket. When the leak crops back up again, I'll try your suggestion & double up on the gaskets.

 

The gasket from the filter fit perfect on the inner ring and I have not had a drop of oil leak from it. Very pleased.