If republicans lose the presidential election, they could take up the nomination during the lame duck session after the election.
If they lose the presidential election I’m sure that’s what they are going to try to do but remember the GOP senators the day after the election will be looking at their chances in 2018 and suddenly saying never mind will not play well.
The chances of losing the GOP Senate are much greater than winning the Presidency. No matter who is elected President a Democrat Senate will only confirm someone much more liberal than this guy