who can stop a late game tryndamere

A late game Nasus.

Anyone with attack speed slows, CC, or potential to kite, or otherwise keep up with his rate of lane pushing (aka, able to clear the minions before he can get them to tower).

just to name a few :^D

People have really weird ideas about who can fuck with Tryndamere late game.

Irelia, Darius, Graves, Yasuo, Kayle, probably Yorick, Riven, Malphite, Ahri, Akali, Annie, Cho'gath, Illaoi, Lissandra, Lux, Malzahar, Morgana, Olaf, Singed (kind of, a good Singed shouldn't be caught by Tryndamere), Skarner, Teemo, and Zed are dumpstered one on one by Tryndamere, and he can easily dive plenty of those, especially the immobile and squishy fatasses like Lux or Malzahar (QSS bitches).

That said, the counter to Tryndamere late game is destroying his team in the 5v4 and winning the game. Or beat him 1v1 with Nasus and potentially Jax.