Traditionally judges need to be confirmed by 60 senators to break a filibuster. If the democrats have 41+ senators that really oppose Gorsuch they could kill his nomination with a filibuster and there is nothing republicans could do under traditional senate rules. A few years ago the democrats and Harry Reid changed senate rules to a simple majority of 51 senators to get a whole bunch of Obama's dirty work done (such as federal judges). It was/is seen as a hostile move.
The Gorsuch nomination will not need the "nuke" option. He will be confirmed with 60+ votes. The democrats will huff and puff to pander to their bases, but in the end they will cave.