Yes you can use that single point to run S/C if you have the required license. You can't crossover your IHRA license for NHRA unfortunately. First you need to establish a NHRA Registration login (after having your S/C # and license of course) and start here....
http://www.nhraeventreg.com/
Without being registered you can still see event statistics (quotas, # of entrants, etc.) and the release dates for events based on number of grade points you have. Registration is a a several step process but once you get there you'll see your grade points and can then select categories (classes) and events that you're eligible for. S/C is one of the fastest classes to fill up so good luck getting in with a single point at Charlotte. Give it a try and if you get hung up don't hesitate to use the "Contact NHRA" icon on the registration screen to shoot them a e:mail. Hope this helps.