What is the legal ruling regarding a fiancé informing his fiancée, who is a nurse—after his prior consent—of his desire for her to quit her job, and his fear of her reaction?

The basic principle is that a woman is not permitted to leave her husband's house for work except with his permission, unless there is a necessity. If the wife stipulated to her husband that she would remain in her permissible work, then she has the right to continue. If he prevents her, she has the right to annul the marriage. If you have not yet contracted marriage with this woman, then clarify to her your disapproval of her work. If she accepts, then she has no right to go out to work without your consent. If she insists, then you have the choice between consenting or dissolving the engagement, unless her work is prohibited, in which case she is not allowed to remain in it, nor are you allowed to permit her to do so.