Nixon no doubt would have received a supermajority of votes in the Senate to convict him (which is why he resigned rather than go through the impeachment process). But this is because his own party recognized his toxicity and cut him off. It will take a similar abandonment of Trump by the GOP in order to obtain a conviction (and this is, of course, assuming that the GOP-controlled House would impeach in the first place).
But would it take on Trump’s part to make that happen? Republicans are oddly slavishly devoted to him. Even though if he went away, they’d still have a very conservative President in Pence who would surely sign off on all their agenda.