House Minority Leader Nancy Pelosi, D-Calif., conducts her weekly news conference in the Capitol Visitor Center on September 6, 2018.

With just six days until Election Day, Nancy Pelosi is confident Democrats will take back the House with more than enough seats.

The House minority leader has been privately expressing to donors and top advisors that she's cautiously optimistic about her party's chances of gaining at least 30 seats in the House.

Democrats need to flip 23 seats to win a majority. Experts give the party good odds to overtake the GOP. Data analyst Nate Silver's FiveThirtyEight gives Democrats an 86 percent chance of retaking the House.

Yet she also has insisted that Democratic election organizations such as the Democratic Congressional Campaign Committee, or the DCCC, cannot let up in their get-out-the-vote efforts with just under a week left until Election Day, according to sources familiar with the discussions.

These people spoke to CNBC on condition of anonymity as these discussions were deemed private.

Pelosi, who will likely become speaker again if Democrats pull off a win, made her confidence clear Tuesday night in an appearance on the CBS program "The Late Show with Stephen Colbert."

"What now I'm saying is, we will win. We will win," Pelosi said during the interview.

A Pelosi aide noted this is the first time she's made such a prediction. She has been more specific about her confidence in private.

A spokesman for Pelosi declined to comment further.