Search "jack stand pad" on Amazon to get a nice selection of options depending on the width of your stand tops. Note that many of them are made for steel pinch welds, not the ~1/4" welded-on bar of the NSX, so have a fairly deep groove. If you're buying stands, lots of folks like Albert86 recommend ones with a flat top, but most stands have a groove to hold pinch welds and truck axles more securely.
I've seen several NSX's jacked with flat tops or deep groove pads, or no pads, and the adjacent aluminum on the frame seems to hold up OK supporting either way - it just gets scratched if pads aren't used. Looking at a cross-sectional cutaway that I saw of that area of the NSX, it's basically a beam section with multiple internal reinforcements, so the tabs may be more of a locater than a critical structural member.
Further, if you look at the way the factory jack mates to the jack points, you'll see it has a groove as well, so the jacking force is actually applied to the flat areas beside the welded-on jack point bars. The beam looks to be extrusion molded so would be way stronger than the welded-on bar, which seems to be designed more for lateral loads in case the ground under the jack is slightly off level. Thus it appears that supporting the bars or the lateral area adjacent to them both work. The rubber pads work well to prevent scratching.
BTW, if you use a pad at the top, be sure that it comes off when you remove the stand or jack. They can tend to stick and then drop off later while driving, never to be found. Don't ask me how I know this.