If you simply want to cut a circular hole in a nurbs object its not hard.

You line up a circle as you want it to appear on the object in one of the viewports. Select the circle and the nurbs object you want to make a hole in and select project curve on surface.

You'll notice this circle is now traced onto the surface of the object exactly as you lined it up in the viewport.

Then you select the object and use the trim tool. You click the areas you want to keep and press enter and a hole is made.

I'd give it a quick try on a nurbs sphere first so you understand whats going on but you shouldnt have too many problems.

Best of luck