Well, no matter what, no one will be confirmed before the election. It takes about 2 months to confirm a justice. Even if a nominee happens tomorrow and everything is expedited, we're still talking about late-November. Nevermind, all the time off the Senate will be taking off between now and January to run for election and holiday breaks.
While they wouldn't get confirmed before the election, I don't believe there is anything technically stopping them from confirming someone in the lame-duck session beyond precedent. I think there are too many Republican senators who would stand in the way of that, but it is hard to say for sure. If Republicans think they are going to lose, they might do a suicide run.