The grammar is just SVC [There] (a dummy subject), [is] (verb), [no stopping her] (noun phrase complement to the subject, a gerund with its object (stopping her))
Compare "There is no water". Or "There is smoking allowed".
As for meaning, it can be glossed as "She can't be stopped".
As for "There is nothing to stop her". That doesn't mean "She can't be stopped". It means "there are no obstacles". It is also used rather differently:
As system administrator there is nothing to stop you from deleting key system files. So remember to think carefully before pressing enter.
Once she had reached college, there was no stopping her. She studied every day, set up a business after graduation, and by 25 she was a multi-millionaire.