Sure you can. However, knowing HOW MUCH nic you have in the extract is the hard part.
Fresh
tobacco, soaked in pure grain alcohol (everclear or similar) for 6 weeks, yes I said SIX weeks will get you ur extract.
then you must find out its potency, and dilute w/PG/VG and so forth. Im not sure we=here, but its talked about on this forum somewhere.
Id say its prob more convenient to find a liquid u prefer and just order it. Not as chaep as DIY, but sure as heck faster!
Good luck!