Looks like the same gasket that commonly
fails on the 5th gen Altima 3.5. For me, it was the gasket behind the timing chain cover. It's built into the cover, so the cover had to be replaced. Mine went out around 80k miles. My extended warranty covered new chains, tensioners, cover with gasket and water pump. Fortunately for me, it only caused a slight ticking noise at start up and no damage was done.
Sound like a used motor is the way to go in your case.