Source: The Great Interpretation of Dreams (Ibn Sirin)
A niece (sister's daughter) in a dream indicates relief and abundance in sustenance.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
A niece (sister's daughter) indicates a world approaching with goodness and blessing.
Source: Signs in the Science of Expressions (Ibn Shaheen)
A niece (sister's daughter) is interpreted as goodness and joy. Whoever sees her will attain relief.