Answer
Based on official Jordanian legal texts
Nushūz under Jordanian law is a wife's departure from the obedience owed to her husband without a lawful excuse, and it directly affects maintenance. Article 62 of the Personal Status Law defines the nāshiz as one who leaves the marital home without a lawful reason, or who bars her husband from entering before requesting a move to another residence, and provides that the nāshiz has no maintenance.
The same Article 62, however, qualifies this: lawful justifications for a wife's departure include the husband's abuse, mistreatment, or her not being safe as to herself or her property; if she leaves for a lawful reason she is not nāshiz and her maintenance does not lapse. Article 61 permits her work outside the home on its conditions.
The effect of nushūz is confined to the loss of maintenance for its duration only; if the wife returns from her nushūz, her maintenance resumes, and the effect does not extend to her other rights such as the dowry.
Nushūz is not established by the husband's claim; it is put to the Sharia Court to assess whether the departure was lawful on the facts and evidence.
This is a general explanation based on Jordanian Personal Status Law and does not replace advice from a qualified lawyer in a specific dispute.