Smiling and appearing relaxed, the Democratic frontrunner carefully avoided references to her opponents, especially her strongest rival, Senator Bernie Sanders.
"I really don't like what the Republicans are saying about immigrants," the former secretary of state told supporters yesterday.
"We are a nation of immigrants, built by immigrants.
"Immigration is who we are, look at us."
Reform of America's immigration system has been a hot-button issue of the 2016 presidential campaign.
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Republican candidate Donald Trump, a billionaire real estate developer who has never held elected office, has stoked the fire by vowing to expel immigrants illegally in the United States and to build a wall on the US-Mexico border, if he's elected.
Clinton accused her Republican rivals of "doing a great damage to our nation by their insults and their attacks."
"So as your president, I will certainly work hard on an immigration reform," she promised, vowing to preserve the executive orders President Barack Obama issued to ease deportations of certain groups of immigrants.
Earlier, Clinton scored an endorsement from the International Union of Painters and Allied Trades.
"I'm feeling really lucky in Las Vegas," Clinton joked after visiting a union training facility.
"Getting the endorsement of this union and the members you represent, and what it means to really focus on the trades -- it doesn't get any better than that."
"We're gonna start by creating more jobs by actually investing in putting people to work to build and maintain our roads, our bridges, our airports," Clinton said.
She vowed to change the tax system so that "the wealthy pay more and give the middle class a tax cut."
"It's time we start rebuilding the middle class," Clinton added.