Answer
$N_{4}Se_{4}$ is $Tetranitrogen\hspace{1mm} tetraselenide$.
Work Step by Step
1. Begin by writing the name of the first element. N -Nitrogen. There are 4 atoms of nitrogen, hence add the prefix -tetra.
2. Since, $N_{4}Se_{4}$ is a molecular compound (two non-metals joined together), we have to use the appropriate prefix for the second element.
3. The second element, selenium, has four atoms. This means we have to use the prefix "tetra" and change the ending to selenide.
The full name then becomes : $Tetranitrogen\hspace{1mm} tetraselenide$