Generally, she can use the deposit to remove the smell. And depending
on the law where you are, she might even be able to get more than the
deposit if the cleaning costs more.
Replacing just the carpet may not do it.
Call a fire smoke damage company and have them come over to produce an
estimate. Be sure they write on the estimate they detect the smell of
smoke, not just that they will remove the smell of smoke. Having a
neutral third party put in writing that the house smells of smoke
bolsters your case. Also, I assume you took pictures of the butts and
pack.
You don't have to hire the company, by the way. You mainly need proof
in case the tenant takes you to court.