Nikki Haley was outvoted in Nevada’s Republican presidential primary by a “None of These Candidates” option on the ballot on Tuesday, according to The Associated Press, an embarrassment in a contest in which she faced no direct competition.

The primary, which awards no delegates, had seemed like a foregone conclusion, as former President Donald J. Trump chose not to take part. On Thursday, he will instead participate in party-run caucuses where all of the state’s 26 delegates will be awarded, a choice by Nevada Republicans that complicated the process and rendered the primary basically irrelevant.

As the top vote-getter after “None of These Candidates,” Ms. Haley is still expected to be declared the victor, according to the secretary of state’s office, which pointed to a state election law that says “only votes cast for the named candidates shall be counted” when determining the result.

But Ms. Haley skipped campaigning in Nevada entirely, choosing instead to spend her time in South Carolina, her home state and where the next primary will take place, after Mr. Trump easily won the first two nominating contests in Iowa and New Hampshire. Ms. Haley is expected to hold a rally in California, a Super Tuesday state, on Wednesday.

Supporters of Mr. Trump in Nevada, including Gov. Joe Lombardo, had advocated selecting “None of These Candidates” on the primary ballot as a protest vote against Ms. Haley. Republicans can then vote for Mr. Trump in the caucuses two days later, where he is essentially running unopposed after Ms. Haley, his last major rival standing, chose not to compete.

Mr. Trump jabbed at Ms. Haley’s ugly result in Nevada, writing on his social media website, Truth Social, that it was a “bad night” for her. “Watch, she’ll soon claim Victory!” he wrote, needling her again over her optimistic speech after she finished second to him in New Hampshire.