Firstly it is not the "Nodal Point"!
You are looking for the No Parallax Point (NPP), Nodal Points have nothing to do with parallax errors. It's an old common mistake, but we should get it correct because we are all far smarter now.
I can help, but I will need more information and more images.
You say "new" Nodal Ninja panohead, is it the M1 series? It appears to be. What rotator is attached? (You shouldn't see the blue knobs in shot) this appears to be backwards. At least the Arca-Swiss clamp should have it's tension knob on the same side as the rotator (blue) knobs so that you never take a picture of them.
Because the Arca-Swiss clamp covers the circle of the rotator I would suggest you place a "CD" between the rotator and Arca-Swiss clamp (or under the rotator) so you have a clear circle to aid with finding your left to right "centre" position as explained in my tutorial. Of course it doesn't have the be a CD/DVD it can be a jam tin lid or anything round with a hole in the centre. This is solely for the purpose of setting your NPP position. Once done (proven correct) this will be removed.
Remember when shooting the rotational set of images we never re-level. Set your level at position 1 and leave it alone and shoot all the rotational images.
Your tilt down only needs to be enough to capture a good edge of the circle object. Don't go to far, because too much overlap will give confusing result from the stitcher.
If you can provide a download link for a "good" set of images in .jpg format I'll happily stitch them up and offer an opinion.