This Isn't necessary the best 1v1 for top, but I'm saying no counters because she can survive top, farm her lane successfully and hold the tower. I have yet to find an enemy champion that can push the lane then dive the tower successfully (meaning getting away with a kill). This build allows her to sustain her lane, and shut down ganks. Which in turn can help your team when the jungler wastes time chasing you around without getting kills. From my experience the enemy always becomes impatient when they can not gank or get a kill out of their lane, so they tend to bring more champions to your lane to dive you and when this happens you can out maneuver them and maybe even pick up a kill, giving your team a chance to pick up dragon, steal a buff, gank another lane, counter gank, or even push a different tower.

Nid has enough mana to lay the traps and heal herself. It is possible. The key is to not spam her spear toss. Really is more important to trap for ganks and sustain a high hp level for this style of high elo play.

AD only affects your AAs and Cougar form Takedown, which you don't get til Lv6. You won't have enough mana in human form to lay traps and heal, not to mention your heals will be ineffective. You'd be better off building AP.

Maw of Malmortius seems more like a situational item to me, since top lane has a lot of AD champions, which would be completely unaffected by a magic-damage shield. I'd rather build Randuin's Omen to kite them like the little kitty you are.

Glyphs should probably be Greater Glyph of Scaling Magic Resist because AP takes longer to get than AD.

Overall...I just don't agree with your build. Even if you aim to play Cougar form the entire game, Nidalee would better benefit from the AP scaling than AD scaling.

And you're supposed to go 9/21/0 to get Weapon Expertise or Arcane Knowledge , not Havoc . Armor Pen is extremely important in top lane.

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No counter, except for Teemo and Irelia. :P