I am trying to replace my kitchen faucet but the nut holding it onto the sink is corroded and the nut won't budge! I have tried a basin wrench (as someone suggested here), wd40, hammering at those notches with a screwdriver and am not getting any movement. How can I get rid of this faucet? I don’t mind destroying it as I have a replacement already in hand.
As somebody in your other question noted, you probably have to attack this from the top. A hacksaw will be time (and arm) consuming. An oscillating multitool with a metal-capable blade would be good though slow-ish. An angle grinder would be fast but will also throw sparks and has the non-trivial risk of having the grinder catch and run into stuff you don't want ground, like the backsplash.
Alternately, you might try to drill out a weakness in the nut with either a large drill bit or linked smaller ones. That would allow you to pry it loose.