Most formal is "Pleased to meet you too", polite is "nice to meet you too" or friendly is "likewise". So I guess that you can say "and you" or maybe "you too".

you can respond with the following sayings:" likewise"," nice to meet you aswell", "pleasure is mine", or" you as well"

It was so great to meet you today

"nice to meet u too " or " nice to know u" or " me too"

you will say nice to meet you too or as you say or you too...