It's probably my age but I always mentally read the Joker as Nicholson. Even when it's in extremely inappropriate stories. and it usually makes me laugh harder when something is funny because it's more absurd that Jack Nicholson is saying it. I dont have this with a ton of comic characters, most all have some sort of internal voice I give them but there's not many I have that are actors that played them, outside of something obvious like if I read a star wars comic I "hear" Mark Hamill and Harrison Ford.
but I do find it a really funny exercise to actively try to read them as specific ones. I read a string of 70s Batman once and tried to mentally get Heath Ledger's Joker in my head when reading those stories and that was entertaining. but Nicholson is one of those ones I do unintentionally unless I try not to. I read some silver age World's Finest story once where Joker and Lex Luthor are robbing a building, only for Superman and Batman to show up to stop them and Joker pulled out a deed to the building saying they bought it, to rob their own stuff and it's legal, and that ACKTUALLY the heroes are harassing them and I read Nicholson saying it and it was surreal and I think I enjoyed it more because of it.
It's odd because although he's great in that movie, I dont altogether think that's a fitting voice for the character, but that's how I read it.