When she is behind you give just a little yank down word and tell her with a click (or what ever ur cue is) and see how it goes:) it worked 4 me:):):):):):):):)
Any 'cue' applied & reinforced consistently & clearly will teach a horse to do something. The reasons I wouldn't use a chain across a horse's nose - aside from disagreeing with using something harsh & potentially damaging across a horse's sensitive nose - are...
While you can teach a horse to respond to any cue, I like to keep things straight forward. I teach my horses to *yield* to pressure, not come into it(well, with the exception of a breastplate or collar when pulling or such). Therefore downward pressure on the nose means yield that nose down/back. IOW lower the head, slow, stop, back up.
Punishment and discomfort absolutely have their place in horse training, IMO. But this isn't *necessarily or to begin with at least* one of them. I think it's vital to use punishment judiciously and with full understanding of the 'cons' as well as 'pros' of it. For starters, I'd be focussing on *teaching* the horse what I DO want, rather than punishing it for what it's doing - which for all we know the horse could have been trained to do, so don't 'come down on him' for it, just politely teach him the alternative behaviour you want.
If you 'ask' gently & politely for the horse to come forward(physical cue is the halter putting pressure on the poll for horse to yield forward), then you can get 'firmer' if necessary(eg use the tail of the rope to put some pressure beside/behind the horse), but IMO being polite & clear is just as important as being assertive & effective if you want to *earn* the respect of the horse.