Unfortunately it is not a Nimcha, but only similar in the handle shape. This sword is coming from Yemen, one of the many types known as
Saif and it is believed to be produced in the island of Zanzibar in the 19th C. The ring shape cross guard is typical to these swords produced in Zanzibar for the Arab market. Below is a similar exemplar:
and a close up on the handle with the ring shaped cross guard:
For a somewhat better specimen please see:
Arab Saif Yemen / Zanzibar