What type of bond is nickel?

Answer 1

Metallic bonds form between nickel and other metal atoms - sort of metal nuclei in a lattice in a shared cloud of electrons - or if you will - very diffuse covalent bonding.

The metal-carbon bond in organometallic compounds is generally of character intermediate between ionic and covalent.

In metalorganics (where the metal does not bind directly to the carbon, but to some other atom in the otherwise organic molecule) the bonds tend to be covalent.

Between nickel and halogens, the bonds have ionic character.

In nickel salts like nickel sulfate, the bonds are ionic.

So - in short - the type of bond nickel forms depends on its valence state and what it is bonding with.