"This is an effort to delegitimize Brett Kavanaugh despite the fact that he was nominated and confirmed," he said.
"They tried to relitigate the Russia investigation -- that didn't work out -- now they're trying to relitigate the Kavanaugh confirmation."
In addition, Gaetz claimed the New York City lawmaker could use his position as chairman of a powerful House committee to work on more pressing issues.
"We really do have serious issues to address in the Judiciary Committee, like reforming our asylum laws," he said, adding Nadler could also work with Republicans like Sen. Lindsey Graham, R-S.C., to draft bipartisan "red flag" gun control laws.
"Those are substantive issues that the American people want to see us addressing," he said.
Agreeing with Gaetz' assertions on Kavanaugh, Fox News correspondent-at-large Geraldo Rivera claimed Nadler is trying to find a victory during his tenure as chairman.
"Their 'Russiagate' hoax did not play out," he said.
On Tuesday, Nadler's committee's top Republican, Rep. Doug Collins, R-Ga., slammed the Democratic lawmaker for what he called "harassment" of Kavanaugh.
"Senate Democrats spent months launching false accusations in an attempt to smear Justice Kavanaugh’s reputation and block his confirmation to the U.S. Supreme Court, and now House Democrats want to follow suit with yet another fishing expedition to tarnish his good name," Collins said.
That day, Nadler -- along with Rep. Hank Johnson, D-Ga. -- wrote to the National Archives to seek "certain presidential records related to Justice Brett M. Kavanaugh’s service in the White House from 2001 to 2006."
They cited the Presidential Records Act, which allows congressional committees to obtain “contain information that is needed for the conduct of [their] business and that is not otherwise available," subject to executive privilege and other limitations.
Fox News' Brooke Singman contributed to this report.