Can we use "nice to meet you" on the phone?
It's not common practice to say "nice to meet you" on the telephone but, if an introduction was made on the call, then I suppose it fits.
Dave: Sue, have you met Paul?
Sue: No. Nice to meet you, Paul.
If it was at the end of the call, a more likely thing to say would be "nice talking to you".
And that concludes the teleconference; nice talking to you, Paul.