I tought you could only put palettes for each 16x16 tiles/2x2 metatiles, but aparently you can put palettes for each 8x8 tiles?
(note: i do know you can't change the palette of each individual tile inside a 2x2 metatile)

(Here's example images from the unreleased Simcity NES prototype with tiles, tiles seperated, palette of each tile seperated and all 4 palettes used)
   

In general, the NES only supports palette switching each 2x2 tiles. However, if you include MMC5 on your cartridge, that mapper would allow for switching palette every tile, among other things. As an example, the Castlevania 3 cartridge has this, which is one of the reasons the game looks so good. You can read more about MMC5 here https://www.nesdev.org/wiki/MMC5