You can play pretty much whatever you enjoy the most but if you are looking to min/max, then Nord wasn't the best choice for Magicka builds.

If you are a DPS go High Elf.
If you are a Healer go Breton or Argonian.
Tanks use all 3 resources most of the time but the general tanking races are: Argonian, Imperial, Nord, and Orc. Best tanking race for Templar is going to be Argonian for the healing received/done buffs and they are only 3% behind Imperials in health but with much better resource recovery.

With that said, Templar tanking sucks compared to the other tanks. You have no AoE CC to control adds like all the other classes have, your resource recovery is nowhere near as good as any of the other classes, your skills are very situational/mediocre, your self healing costs twice as much in most cases, and your group utility while existent is just not as good as other classes.

Now my Templar tank is actually my favorite class theme and is my main, but we just don't have the tools available to us like other classes do.

I chose Imperial as my Templars race back when the game first started but Argonians have been buffed ahead since then. The Imperial still isn't a bad choice but the Red Diamond passive we have could use some tweaking to make it more on par with other racial passives.