Working her first political campaign, Ms. Holland has shown little interest in dealing with mainstream reporters to shape stories about Nevada’s closely watched Senate race — and she didn’t respond to a request for comment for this article. She has used her Twitter account, however, to repeatedly post negative information about Hunter Biden, President Biden’s son, and criticize Senator Catherine Cortez Masto, the Democratic incumbent in the race, for not participating in more TV interviews. Ms. Holland’s posts on Instagram — posing with fellow conservatives or modeling Republican merchandise — have regularly drawn hundreds or even thousands of likes. Several...