(it's) nice to see you
A polite phrase used when meeting and greeting someone. Hey, Jake, it's nice to see you! A: "Thank you for inviting us to the party." B: "No problem, nice to see you!"
(It's) nice to see you.
an expression said when greeting or saying good-bye to someone. Mary: Hi, Bill. It's nice to see you. Bill: Nice to see you, Mary. How are things? John: Come on in, Jane. Nice to see you. Jane: Thanks, and thank you for inviting me.