1) Ramp cards: I don't think Sylvan Caryatid is good enough. Usually these decks have some mixture of Voyaging Satyr and Overgrowth because they are so explosive. Sylvan Caryatid is harder to kill sure, but in modern speed is so important. You also have only 8 one mana ramp cards and I think 10-11 is more likely to be correct. I have 2 Birds of Paradise in this slot.
2) Walking Ballista + Nissa, Voice of Zendikar: I feel like these are too fair cards for this type of deck. To be fair, I have no experience with these cards in practice so maybe these are better than I think. I would replace them with more ramp and more bombs. If you want removal in main deck, I would suggest Lightning Bolt.
3) Mana base: With the above changes in mind, I think 4 Nykthos, Shrine to Nyx is unnecessary. I only have 2 now and it is so much nicer for the mana. I have played various Tooth and Nail and Devotion decks that had Kessig Wold Run and 4 Nykthos, Shrine to Nyx and it is often a pain. I am not sure about the creature land so it may be fine, but I have never played with those in these decks because I prefer speed and want my lands untapped.
I have included my list below. Sideboard is not well tuned.
And in general, what is everyone's opinion of the two different Emrakuls in T&N decks? Where Annihilator 6 is better? Against Ad Nauseam? Emrakul, the Promised End has trample so she kills in one shot too and is way easier to hardcast. Usually I cast her for 10 mana and I feel like that is more relevant than Annihilator 6.