bring your tools, go to nearest autozone/pepboys and have them scan the car dep on if its ODBI or ODBII make sure that the problem, then buy some jack stands for 40 bucks, use your 02 sensor removal tool for your other Honda you have done,
make sure you put the correct flow 02 sensor in the right spot dep on year you could have 4 of them for different flow, if you NSX has aftermarket headers
make sure the new 02 sensor plugs match, airtools if you cant get them off, lube them if they are stuck, doing this in the autozone parking lot in the baking sun, bring sun tan lotion, bring clothes you don't care about cuz they will get dirty since you didn't bring your laydown board with 10 small wheels to scoot under the car, after install start car and see if that's the problem because all that work would be in vein if the check engine light was for another error since you trust the original owners diag. and we all work on our own cars but there is a time and a place that paying a little is worth the money.
if your worried about a 100 bucks then your not gonna like the NSX its not a Civic or Accord or S2000 a rear quarter is 2900, clutch parts are 1800
brake pads are 250 for front 160 rear,
and after wrecking it the first week like many have done your wallet crys LOL