Which of the enchanters best scales into late game for the support role?

Tie between taric and sona imo, but if i had to pick one taric.

That's Sona's biggest thing: late game.

I feel like nami does well later too with her bubble and ult. Morgana needs money to get AP but her snare is still good.

but only a single target. and for late game team fights.

These 2 right here. Every other single support you mentioned is completely and utterly useless by comparison. Janna shield is an ad riod. Nami has infinite healing/poke

Both take next to no skill to play. Can you click your adc? GOOD here's challenger.

- easily. Everything else is debateable.

score high in this regard.

And I wouldn't call an enchanter. ^^