One of the ways to stall a bill is to talk about it forever. Here’s the wiki explaining it.
Technically speaking the filibuster is only acceptable because the rules of congress allow them, but the rules are changed and Agreed on by all members every year. So “nuke the filibuster” would mean to disallow it in the procedural rules of congress.
I don’t know as though that is a law, but with the new Supreme Court ruling on presidential immunity, it is a valid possibility. If “murdering your political rivals” is on the table, then “sentencing a terrorist to death” is probably covered.