Joker has been played by the best male actors of their generations. One of them is definitely Jack Nicholson's version in Tim Burton's Batman Begins. So it makes sense that he would be given an homage in Todd Phillips's Joker movie. But there is no grandiose homage, instead it is a very subtle one.
Robert De Niro has played a lot of psychologically affected characters, but one of his performances in a Scorsese movie might have been used to intentionally parallel it with Arthur Fleck's journey into madness.