One of the reasons the confirmation referendum was intended to be held earlier in the months for nominations was so that the nominations for the Court could take place before people decided whether to run for elected offices.
This time, of course, the delay creates the problem that candidates aren't willing to consider dropping out in order to accept an nomination. It might be necessary at this point to just wait until the election is over.
Otherwise it might look like a nomination is a trade-off during the actual election, and that would also present a problem.
I think there are possible Assoicate Justices among the current crop of candidates, but it makes no sense to even raise the possibility at this point while voting has started and campaigning continues.