Can it be done?
If I use a sample for drums, is there a way of setting the song tempo to match the sample?
Not with n-Track (as far as I know)
If the sample tells you what bpm it is then just set it manually.
Other programs (like Acid) have a beat detector feature that may be able to tell you what the tempo is. There is a free version of Acid but not sure if it has that feature or not…