Censor.NET reports citing Reuters.
"I think this is something that needs to be investigated and addressed," Coats told the Senate Intelligence Committee during his confirmation hearing.
Coats, 73, a former member of the intelligence panel, also promised that it would have full access to all of the documents and other materials needed for an investigation.
Trump denounced intelligence agencies for their assessment that Russia sought to influence the election on his behalf, prompting concerns about his support for them. Trump has also repeatedly praised Russian President Vladimir Putin, leading some in Washington worry that he might not take a hard enough line in dealings with Moscow.
"I have no intention of holding anything back from this committee," Coats said.
In his opening statement, Coats addressed that concern by listing activity by Russia, along with that of China and North Korea, as among the main challenges faced by the United States.
"Russia's assertiveness in global affairs is something I look upon with great concern, which we need to address with eyes wide open and a healthy degree of skepticism," Coats said.
Although he was ambassador to Germany under President George W. Bush, Coats would be the first director of national intelligence who has not spent most of his career in the military, in intelligence agencies or as a diplomat.
Coats, who is popular with Democrats and his fellow Republicans, is expected to be easily confirmed.