Designated competent authority(ies) to issue an apostille in Nicaragua:

Ministry of Foreign Affairs of the Republic of Nicaragua

How to apostille in Nicaragua?

The competent authority is the Consular General Directorate of the Ministry of Foreign Affairs. The owner can appear in person at their offices or send the documentation by courier, after downloading the form on which the apostille request is made.

General Links:

https://www.hcch.net/en/states/authorities/details3/?aid=943