It's a lot of parallels between these two when you think about it.
Both of them famous for holding the secondary title in their promotion despite being main event level guys
Both known for unorthodox martial arts style offense
Both have that swag of being cool, laid back guys that could nonetheless whoop 95% of the locker room's ass in a shoot if need be
Both had their peak before WWE then went to New York and started mailing it in/cashing checks
I'll take Nakamura because I think he's a little less one-dimensional than RVD in-ring. I love RVD, stanned him heavy as a kid but if I'm being honest, he never really brought the emotional aspect to his matches. As athletic contests, his bouts with Jerry Lynn are legendary and rightfully so, but they don't really have the same drama and epic feel as Nakamura's best matches with Ibushi, Tanahashi etc.
Also, being objective, NJPW during Nakamura's era is a bigger stage than 90's ECW.