It was nice to talk to you.
My response might depend on exactly who I am talking with, but I can think of the following which I would say at least some of the time.
Note, since this is saying goodbye, or "leave-taking," it's okay to repeat the same words or use similar words (similar to greeting: A: How are you? B: Fine, and how are you?)
Polite:
-Yes, it was nice to talk with you too. (polite)
-Nice talking to you too. ("polite")
-I feel the same. [I hope we can do it again some time {polite}. Or Let's do it again sometime. {casual}] (polite, and definitely gets the point across; I mean you are admitting some feelings here)
Friendly:
-Same here. Nice talking with you.
-Yes, same here. I'll talk with you later. (but only if you mean it)
-Hey, it was great to talk with you too! (friendly/enthusiastic)
-Good chatting with you too!
Informal:
-Yes, catch you later! (more informal, use with a good or frequent chat buddy only)
-Yes, same here!* (pretty informal)*
If you are in a hurry:
-Me too. (I would probably not actually say this one, but 'me too' seems to be used more and more these days as a generic response, even if the logic doesn't work: A: It was good to see you again. B: Me too.) As a texted response, it would be okay with a friend.
-Okay, me too, see you!! (This one sounds better because 'me too' is not by itself.) But it does sound as if you are in a hurry to say good bye.
But not:
-I think so.
Last, apparently 'talk' or 'speak' to someone is British English, and 'talk' and 'speak' with someone is American English (generally speaking).