To embed a graph inside NagVis maps i only know the way to make a dashboard with this graph as element and use this dashboard inside NagVis iFrame element.
Like this
With enterprise edition this was also before 2.0 the only way to have good graphs inside NagVis if you don’t want to mess around with the image export feature.
But pay attention the iFrame element looks again really broken at the moment. You start modify the element and cannot finish. Your cursor is sticky on one edge of the frame and don’t let loose.