It depends on what kind of oil they're using, conventional or synthetic. A fair price for an oil change with conventional oil is $30-50, and with 100 percent synthetic oil, $50-70. (The oil filter lists for $14, and the car needs 5.3 quarts of oil.) If you bring your own oil, then it should cost $25-40. Most dealers don't stock synthetic 10W30 oil (the viscosity recommended for the NSX), and many don't even stock conventional 10W30. If they don't stock the kind of oil you want to use, most will be happy to change the oil using oil you bring them. And you can usually save money by buying a case of Mobil1 10W30 at Costco or Sam's Club for ~$24.
Also note that there is nothing requiring NSX experience to do an oil change; any competent independent mechanic should be able to change your oil. If you use an independent, I would suggest buying the stock oil filter from your Acura dealer, and a crush washer with it (tape it to the filter so it doesn't get lost), and bring it to your mechanic. If he doesn't carry the oil you want, bring that too.