Pretty much what the guys have said. The big difference is that nickel tarnishes - quite quickly - and chrome basically doesn't.
So if you look at, for example, an old Strat, the nickel-plated tuners and saddles will have a dull grey patina but the chrome-plated bridge and jackplate will still be shiny. You sometimes see see chrome hardware where the plating has cracked and flaked a little, but even that's pretty rare.
When they're new, they're both shiny and silver - but nickel has a slight hint of yellow in the colour, whereas chrome is blue/white like a mirror.
For your Tele, the original pickup will almost certainly have a chrome cover so chrome would be more "correct" - but it's up to you.
