$Z =$ Atomic number of the metal

$X =$ Number of electrons lost during the formation of the metal ion from its atom Y=Number of electrons donated by the ligands

For $\left[N i(C O)_{4}\right]$

$E A N=Z-X+Y=28-0+8=36$

For $\left[N i(C N)_{4}\right]^{2-}=28-2+8=34$

Thus the EAN of $\left[N i(C O)_{4}\right]$ and $\left[N i(C N)_{4}\right]^{2-}$ is not the same.