Your horse is probably not desensitized to the nose chain, but maybe you have not used it in a quick and firm downward jerk. Even your being a small person with the nose chain it should be of some help in controlling your horse, but then a rope halter would also you more control than a flat one.
For a horse that "sits back/ pulls" when tied can be helped by double tying it. When I first got my mare she would "sit back" when tied until it was suggested to me to double tie her. What I did was put a neck rope on her that had a very tight slip-proof knot in it. The loop was just big enough to slip over her head then I put her halter and lead rope on her. I tied the lead rope first then tied the neck rope only slightly longer. When she sat back/pulled if she broke the lead or snap the neck rope still had her tied. After a while she stopped sitting back and pulling altogether.