I often find myself struggling to come up with a response to that simple sentence. The only thing I always end up saying is "same here" which, to be perfectly frank, I'm not sure is appropriate. I'd appreciate it if you could suggest some more responses for me to add to my collection of responses.
"It's good to see you too".
You don't need a fixed reply. You talk about the situation:
Hi Amin, it's good you see you.
Hi John. Do you have the quarterly sales figures I asked about last week?
Good you see you too! It's been, what? five months since you were in the Bombay office?
You too! I'm just visiting to audit the research division.
and so on. You don't have to use a collection of responses.