Appropriate to say "Nice to meet you" over a phone interview? I have a phone interview for a tenure-track position. It's always awkward because you want to say "Nice to meet you, Prof. X" but it sounds so weird. What would be the alternative? You wouldn't just want to say "Hi Prof. X". Would you?
There are surely plenty of alternatives.  "It's a pleasure to speak with you."  "Thanks for taking the time to speak with me."  And so on.

However, even if you do say "Nice to meet you", the most that will happen is someone will say "Though I guess we're not really meeting, are we?  Ha-ha-ha."  And you'll say "I guess not, ha-ha-ha" and chuckle politely for about half a second, and then move on.  Nobody will care or remember, and it will have no effect on the outcome of the interview.