What does “nice knowing you” mean?

“Nice knowing you” is an expression that people use when they’re saying farewell to each other. It’s not very lighthearted or casual, and you will find it used in very emotionally heavy situations, and it expresses a beautiful sentiment in which you will miss the person involved. Martin holds a Master’s degree in Finance and International Business.

What does it was nice to meet you mean?

"Goodbye, it was nice to meet you." "Nice to know you" means something quite different. You say "to meet you" after you are done meeting them. You say "to know you" after you are done knowing them. In other words, this is what you say when you are saying farewell forever: "Too bad you're moving to Texas. It was nice to know you."

Are “nice knowing you” and “nice to know you” accurate?

Both “nice knowing you” and “nice to know you” can be accurate, they’re just in different verb tenses. “Nice knowing you” is short for “it has been nice knowing you”, and “nice to know you” is short for “It was nice to know you”.