FDS is the same thing as NES.
The reason you can't see it is:
1) Either the particular game uses compressed graphics.
2) You need to scroll to a particular address, increment/decrement the address by 1 if you get something looking close to correct.
3) TLP is old and a little dumb. I don't think it was dumb enough to assume NES games always had CHR-ROM, but I recall it did assume SNES ROMs always had headers (yes, even in 2000 or whenever that was written it was a bad assumption) (which in 2021 headers should be eradicated from existence, I hear they weren't even reliable for the ancient copiers they were designed for, if you were still even capable of using the obsoleted forms of PC communication they had).
But still TLP probably doesn't recognize the FDS extension, so you'd probably have to force open the ROM and then manually select the graphics mode.
Otherwise use literally any other tile editor. Surely NES is one of the most commonly supported formats.