The only challenger to Donald Trump for the Republican presidential nomination, Nikki Haley could finish second in the race – despite being the only candidate. Trump’s supporters have been urging party loyalists in Nevada to write in “none of these candidates” on their ballots. Haley is the only serious competitor for the party’s nomination to Donald Trump. The candidate is standing in tonight’s ballot, after choosing to contest the primary election rather than Thursday’s caucus – in which Trump will take part. Polls suggest the 52-year-old, who has largely ignored Nevada during her campaign, …