Built in Nike+ is, by default (new off the package) turned off on the 2G touch. You need to manually turn it on. To turn it off/on, go to settings and then on the bottom is the Nike + iPod setting.
I can get to the settings for Nike + but there is nothing to calibrate a remote.
When I plug the dongle it says that it cannot use it because it is already built in. Uuuugh