Long thin tris are not ideal with traditional geometry or nanite, with normal geo it causes more quad overdraw and with nanite it makes it harder for the mesh to create and use triangle clusters effectively.
But also long thin tris are somewhat inevitable. What I do is deliberately terminate triangles as soon as possible (if you have a hole in a plane, don’t have the tris go all the way to the corners of the plane, but have a square that it terminates to just around the hole). And add more edge loops so the long tris aren’t quite as long, sometimes it’s a split every 30 cm.