Nikki Haley isn’t shy about saying “told you so” — and she’s sitting on a real doozy now.

Back in January, after she lost the New Hampshire Republican presidential primary, our former governor issued an ominous prediction.

“Most Americans do not want a rematch between Biden and Trump,” she said. “The first party to retire its 80-year-old candidate is going to be the party that wins this election.”

She was, at the very least, half-right. Nobody wanted that sequel, but primary voters gave it to us anyway.

And on Sunday, President Joe Biden canceled that matchup sort of like the studio axed the sequel to Kevin Costner’s new Western. Biden announced that he wouldn’t accept the Democratic nomination for re-election.

Which means GOP voters may have wished they’d listened to Nostradamus Haley. Who, by the way, also said this in January:

“If Donald Trump becomes the Republican nominee, we will get a President Kamala Harris. You mark my words,” Haley said. “He cannot win a general election. He can’t get independents. He can’t get suburban women.”

Again, not rocket science. But no other Republican candidate had the spine to say it out loud.

Fast forward six months. Now, Republican nominee Donald Trump is the oldest presidential candidate in history, and even if Harris isn’t the ultimate nominee, the Democrats will certainly nominate someone younger than Trump.

And here’s where this comes back around to Haley again.

Trump was so confident of his chances in November that last week he selected Ohio Sen. J.D. Vance as his running mate — a pick that is, to say the least, uninspired and unexciting.

Never mind that Vance once called Trump “America’s Hitler” — which you can bet we will hear ad nauseum for the next three months — he doesn’t expand Trump’s appeal. Vance delivers nothing but some money from tech guys and Ohio, which Trump was almost certainly going to carry anyway.

Haley, on the other hand, has been the clear choice of the anti-Trump wing of the Republican Party — she was taking up to 20% of the primary votes in states after she dropped out of the race.

Which should have set off alarms with some folks at Mar-a-Lago.

But Trump was so mad that Haley ran against him, and actually had the temerity to criticize him, that he once said he didn’t need or want her voters. Bigly mistake.

In fact, it wasn’t until after his assassination attempt — when Trump reportedly decided to change up the Republican National Convention’s messaging — that Haley even got invited to speak at his coronation.

And it didn’t go well. Haley took the stage in Milwaukee last week to a mixture of cheers and boos, and most pundits judged Trump’s reaction to her remarks as “unimpressed.”

Now, Haley has upset many folks. The MAGA crowd because, well, see above. And she’s enraged those who backed her in the primary because she eventually endorsed Trump, which she made people think she would never do.

Of course, she’s just trying to stay relevant in the party, assuming there will be one by the time the next election rolls around.

In her convention speech, she tried to give herself some cover for that regularly scheduled rehabilitation.

“You don’t have to agree with Trump 100 percent of the time to vote for him,” Haley said. “We agree more than we disagree.”

But that isn’t playing well with her former supporters. On Sunday, within hours of Biden’s announcement, the political action committee “Haley Voters for Biden” changed their name to “Haley voters for Harris.”

So that’s how it is.

For the moment, Vice President Harris is said to have enough commitments to be the Democratic nominee. But if the delegates at the Democrats’ convention change their mind and upend that, or even fill out the ticket with one of the big stars on their bench — Pennsylvania Gov. Josh Shapiro, Michigan Gov. Gretchen Whitmer, Arizona Sen. Mark Kelly (all from vital swing states) — well … that’s a whole new ballgame.

Haley on the ticket could have helped Trump broaden his appeal in the suburbs and among women — who, make no mistake, don’t all love the former guy.

Women tend to not like men repeatedly accused of sexual harassment, or worse, and who take away their bodily autonomy.

So where does this leave Haley?

Well, she’s considered a possible contender for secretary of state should there be a second Trump administration (but beware of the Mitt Romney switch-and-shame dinner, governor!), or she could be a front-runner for the GOP nomination in 2028.

All that’s a long time off.

But if more folks had listened to her, she very well could have become Vice President — or even President — Haley in January.

It doesn’t take Nostradamus to see how that would’ve played out.