An argument can certainly be made for Miss Emily's status as a victim of the values of her era. Chivalry, as you mention, is a value to which Miss Emily ironically clings, albeit largely by implication.
As a young woman, Emily's father protected Emily from men with such force and determination that she became a spinster. This protection is directly related to chivalry as it indicates a specific concern for honor and a specific mode of inter-gender relations.
The over-protective stance of her father leads Emily into a rather helpless position. When he dies, she must "cling to that which robbed her" of a chance at a normal life. She clings to the isolation that had been forced on her. This state of isolation is the only thing she knows.
Her father prevents her from dating anyone because he doesn’t believe any of the men in Jefferson are good enough for her, and after his death, Emily continues to isolate herself from the rest of the community for the better part of her life.
Unable to develop a normal life along normal lines, Emily becomes twisted. In her forced isolation, she loses touch with her community and, importantly, its morals. She did not teach herself this isolation, however. It was taught to her, as it were, by her father. In this way, we might argue that Emily is a victim of an over-protective father.