The "nuclear option" to me is more accurately described as the "Reid Rule." And it's a bit misunderstood. The Senate passes "Rules" to start each session, and before Harry Reid the Senate never changed the rules mid-session. One of the rules was the "Cloture" rule. https://twitter.com/Aossai/status/1307731987126464514

Cloture is a process to end debate -- it is the process to close down a filibuster. It starts the clock ticking on the final hours of matter can be debated on the floor before a vote is taken. The practical effect is that it EXTENDS debate.

That is because the alternative to "cloture" was a "unanimous consent" to end debate and proceed to a vote. Dems have refused unanimous consent requests since the start of the Trump Admin., greatly slowing down the confirmation process of Exec. branch appointees and judges.

For a long time the "cloture" vote required 67 votes to pass -- just to start the final clock running on the time to debate before moving to a vote. Without 67 votes and with no unanimous consent, debate would never end -- hence a "filibuster" was underway.

Some time ago, at the beginning of a Senate term, the Rule was changed --- at the time Rules have always been changed -- to reduce that number to 60. But without 60 votes to invoke cloture, debate could not be brought to a close.

What Reid changed was the rule about when Rules could be changed. Unable able to get 60 votes to invoke cloture on Obama judicial appointees, he had the Senate vote mid-session to change the rule, reducing the votes needed from 60 to 51 to invoke "Cloture" on lower court judges.

Now the same majority that could confirm a lower court nominee could also vote to end debate on the nomination.
But the real damage was Reid's decision to amend the Senate Rules mid-session to suit his own purposes.

So when the Gorsuch nomination came up after the GOP took control of the Senate, and there were not 60 votes to end debate, McConnell invoked the Reid Rule that allowed the Senate to amend the rule mid-Session and changed the "cloture" rule for Supreme Court nominees.

Reid was warned at the time he created the "Reid Rule" that the unintended consequences of what he did for a handful of Appeals Court judges would come back to haunt the Democrats later. I happy he has lived to this day to see that prediction come true.