SO
so + adj/adv
They are so nice.
*make the meaning stronger;
e.g.He talks so quietly.
* meaning "like this";
e.g. I don't usually get up so early.
SUCH
such + noun
They are such nice people.
*make the meaning stronger;
e.g. He's such an optimist.
* meaning "like this";
e.g. How can you say such a thing?