I would try making a backup copy of your game, and reducing all textures by half, i.e. 2048 to 1024, 1024 to 512, etc...

This way, you can see if the problem is fixed, and also see if you can live with the smaller texture sizes. I was not thrilled to reduce all my texture sizes, but it's better than having the game crash.

Also, I believe you can go up to 500 with your nexus. I know the manual recommends keeping it lower, but I think that was written a long time ago... this could give you some extra needed memory.