Nimer said he jumped into the race on the fly after county party officials contacted him on Wednesday to see if he would be willing to replace Nancie Lee Davis, who lost her spot for failing to file a campaign finance disclosure.
State law allows parties to replace a candidate if he or she dies, is found physically or mentally unable to run or fails to file the proper disclosures.
In addition to Davis, Republican Jerry Anderson was eliminated from his challenge to Rep. Christine Watkins, D-Price.
Nimer, 60, is president and owner of New Start Business Services Inc., an accounting and tax consulting company, and is president of the Utah Log Cabin Republicans, an organization for gay GOP members.
Nimer said he believes sexual orientation will not be an issue in the campaign. Voters have shown their willingness to vote for a gay candidate when they elected Scott McCoy to the Senate in 2008, he said, and McAdams has been a strong ally to the gay community.
"More than anything else, what I'm doing is giving the Republicans and independents an alternative to vote for," Nimer said. "I bring a different viewpoint to this stuff. I am a conservative Republican as far as limited government and individual responsibility."
If he wins, Nimer would be the first openly gay Republican legislator in the state. There have been three gay Democrats in the Legislature. Nimer said he doesn't anticipate any problems with the Republican caucus, which includes several conservatives who have been hostile toward gay issues.
"I'm not a new kid. I've been a Republican my whole life, and I know a lot of people on the Hill already. They're friends and associates of mine," Nimer said.