when we TT'd DD#1 we still used nappies at night, even though we went straight to pants during the day.
When she woke up dry we gave her lots of praise and she was able to put the same nappy away again to use the next night.
After about 6 mths she decided she didn't want to wear a nappy at night anymore, so now we take her to the toilet just before we go to bed at night. She is still usually sleeping, so isn't really learning to go to the toilet overnight - but I'm not too fussed at the moment. She's only just 3