RM2K(3) used a different terminology, what was called chipsets then is called tilesheets now
there are almost no direct, preformatted chipsets (they would be in https://forums.rpgmakerweb.com/index.php?forums/rm2k-3-resources.133/
) , but you can find tiles and tilesets and need to use an image program to reformat them to use them in RM2K(3).
That is more work, but unfortunately the only way - the problem is that most original RM2K(3) sites were pirate sites and it's almost impossible to filter out the legally available resources from ripped resources on those sites even if they still exist.
And the formats of RM2K(3) are too old for newer resources to use them - all resources here on this site use later RM-Formats, and the same goes for other websites like opengameart, you'll have to reformat them yourself to be able to use them.
That is practically the only way to get legal usable free resources for RM2K(3) today, without risk of unknowingly ending with rips.