She has it all to do if she is to weaken Mr Trump’s stranglehold over their party after a strong showing in the Granite State that nevertheless left her a distant second.
Ms Haley and Mr Trump next find themselves heading west and thrust into one of the most bizarre electoral systems in the 50 states, where two competing nominating contests are being held.
Because why choose between a primary and a caucus when you could just have both and confuse everybody?
Here’s a quick guide for the baffled.
Whereas Iowa operates a traditional caucus system for choosing its presidential candidates and delegates, requiring voters to show up in person to party meetings at which they signal their preferences, New Hampshire opts for the more modern primary model in which voters cast ballots much as they do in a November presidential election.
This year, Nevada is playing with fire by staging both state-run Republican and Democratic primaries and a separate party-run GOP caucus, effectively giving registered conservative voters two opportunities to pick their preferred candidates for the Republican nomination.
The state-run primaries are scheduled for Tuesday 6 February while the Nevada Republican Party’s caucus will follow two days later on Thursday 8 February.
Significantly, the caucus requires entrants to pay a $55,000 fee to participate (or $35,000 if they have agreed to take part in a Nevada Republican Party fundraiser).
That issue has divided the candidates seeking the GOP nomination into two pools.
As it stands, the primary will be contested between Ms Haley and three lesser-known candidates – John Anthony Castro, Heath V Fulkerson and Donald Kjornes – and will surely result in an easy win for the former UN ambassador.
Mike Pence and Tim Scott were previously scheduled to take part but have since suspended their campaigns, although their names will still appear on ballot papers.
The caucus will meanwhile be fought out between front-runner Mr Trump and Texas pastor Ryan Binkley, after Florida governor Mr DeSantis ended his campaign on the Sunday prior to New Hampshire.
The other crucial distinction between the two events is that only the winner of the caucus will wrap up Nevada’s 26 delegates, so the victor in the earlier contest will have only a symbolic triumph as a reward for their troubles.
The caucus is therefore the only one of the two competitions that will have a meaningful bearing on the hunt for the GOP nominee for president.
What has brought this madness to pass?
A bipartisan bill passed by Nevada’s state legislature in 2021 stipulated that the state must hold political primaries if more than one candidate is in contention for a given race, doing away with the old party-run caucus system the Silver State has traditionally employed.
While the Nevada Democratic Party has cheerily accepted that and both Joe Biden and challenger Marianne Williamson have filed the necessary paperwork to take part in its primary, the Nevada Republican Party is insisting on carrying on with its preferred caucus in addition to staging the now-mandatory primary.
The party did try to have the primary requirement dismissed in court last May and was thwarted, although it did succeed in ensuring that the award of delegates to the winning candidate would only take place as part of the caucus contest, thereby rendering the primary a somewhat empty formality.
What does it mean for the candidates?
The merits of the two formats have been hotly debated in recent months, with some conservatives insisting a caucus is more transparent and therefore less vulnerable to fraud and Mr Trump’s camp in favour of it because it plays to the strengths of the extensive organisational network he has established in Nevada.
While you might think that the lack of delegates would deter major candidates from participating in the primary, Ms Haley, Mr Pence and Mr Scott did all agree to take part, if only to save themselves the hefty caucus entrance fee.
Speaking to ABC News, the Nevada Republican Party chairman Jim DeGraffenreid said recently of Ms Haley: “I felt like she was still planning to be competitive. Of the three of them, I think I was most surprised that she chose to forego delegates here.
“It remains to be seen how voters will react to that. Anybody that understands the process understands that delegates is the goal of every primary or caucus in the nation, so I certainly am perplexed as to why any serious candidate would file for a contest that doesn’t allow them any delegates.”
Ms Haley’s decision not to pay up and enter the caucus suggests she may not have much confidence that she can out-do Mr Trump in this first-in-the-West contest but being able to say she has won the state’s Republican primary might deliver a timely messaging boost when she needs it most, even if it does not yield delegates.