She will have control of the House for the next two years, so this should be a matter of significant concern for us. She's specifically talking about gun registration in the form of so-called "universal background checks". In practice that means that every time anyone buys or sells a gun, they have to be background checked, and that check creates a government record of the sale. Transferring a firearm without a background check would immediately become a felony, and any firearm in your possession without a matching record with a manufacture date after the legislation took effect would be a presumption of guilt.
Now, the good news...
Pelosi's comments came immediately after a mass murder in California, which already is practically a gun control paradise. That won't help her argument and passion is likely to cool before the new Congress is seated.
Furthermore, gun control has passed the House before. The Senate is the more difficult hurdle. Republicans still hold the Senate, and even increased the margin a little. However, many of our Senators are a bit wobbly on this, and Trump is a bit of an unknown. He's already backed a bump-stock ban and he has New York attitudes about guns. We don't want this to get to Trump's desk.
Schumer probably can't count to 60 on this, but "universal background checks" are a recognized point of political weakness. We know they don't work but politicians find it hard to vote against them.
It seems likely Pelosi's real goal is to excite her base and force a vote on the record, then use it to fundraise and go after vulnerable 2020 senators.
Worse, this is a declaration of war from the Democrats. They no longer believe that gun control loses elections.