How do you write the electronic configuration for $ N{i^{ + 2}} $ ?

Hint :The distribution of electrons in an element's atomic orbitals is described by its electron configuration. Atomic electron configurations follow a standard notation in which all electron-containing atomic subshells are arranged in a sequence (with the number of electrons they hold written in superscript).

Complete Step By Step Answer:
Electronic configuration of Nickel ( $ _{28}Ni $ ) is:
 $ 1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}4{s^2}3{d^8} $
Two electrons of Nickel are removed from the outermost shell. The electronic configuration of $ N{i^{ + 2}} $ is
 $ 1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}4{s^0}3{d^8} $
The following are the three rules that govern how electrons are filled in atomic orbitals:
The Aufbau principle states that before occupying an orbital associated with a higher energy level, electrons must completely fill the atomic orbitals of the previous energy level. In order of increasing orbital energy level, electrons occupy orbitals.
No two electrons can have the same values for all four quantum numbers, according to Pauli's exclusion principle. As a result, each subshell of an orbital can only hold a maximum of two electrons, both of which must have opposite spins.
Hund's maximum multiplicity rule states that all subshells in an orbital must be occupied singly before any subshell can be doubly occupied. Furthermore, all electrons in singly occupied subshells must have the same spin (in order to maximise the overall spin).

Note :
By assisting in the determination of an atom's valence electrons, electron configurations provide insight into the chemical behaviour of elements. It also aids in the classification of elements into different blocks (such as the s-block elements, the p-block elements, the d-block elements, and the f-block elements). This makes it easier to study the properties of the elements as a group.