Kruphix Anti-LD

First order of business, producing mana from non-land sources. In addition to what you're currently running, i'd suggest gilded lotus, thran dynamo, and mana vault. When you lose all your lands, these will provide the greatest opportunity for a comeback; all are better than the diamonds and the cluestone (dark steel ingot is probably better than clue anyway).

Since Nick's deck likes board wipes as well as land wipes, I'd be very selective in which creatures you run and how many. Creatures to cut: Elvish mystic is probably unnecessary with your artifacts. Hooded hydra doesn't do much with your big mana although it is good in hydra tribal (same with sprouting hydra); also, morphs need to be run in multiples for any sort of illusion to work. Phyrexian Hydra is really unnecessary outside of dedicated infect. Simic guildmage isn't very impressive, and zameck guildmage is kind of borderline. I see the laboratory maniac, enter the infinite, omniscience combo... if you really want to run, I say go for it, but it can be a glass cannon. Simic manipulator seems good in theory but I don't think he'll perform.

Creatures (and other stuff) to add: If you find a way to build around sage of hours, that would be awesome. Increasing savagery, blessings of nature, hunter's insight, soul's majesty, and any good auras might help with that. Mossbridge Troll could be really cool in this deck. Tilling tree folk and life from the loam do well against LD. Creeping renaissance naming land works. Paetor's Council is bomb. Thadda Adel can yank Nick's artifacts before he can play them. Far wanderings is the perfect card to come back from an LD strike. Seedguide Ash grabs a bunch of lands post LD. Meloku, the clouded mirror both creates tokens and protects your lands; I'd play it with explore or burgeoning for maximum effectiveness (those two cards are really solid on their own, too). Soratami Savant and Uyo, Silent profit can pull lands for good effects. Time stop can end the turn with spells on the stack so they don't resolve- It's basically a multipurpose counter spell. Glen-eldandra arch mage is insanely good at delaying LD. Yavimaya Elder excels at restoring land bases. Eternal witness should be in here. Solidarity of heroes synergizes nicely with this deck. Stroke of genius and other X draw spells benefit from big mana- I'd recommend 1 or two of them. Mystic snake is a nice counter spells, as is voidslime. I like coiling oracle in my simic decks as an early game value creature. Trygon predator rips up Nick's deck, I highly recommend it. Momir Vig serves as a nice tutor for utility creatures and game enders. On that note, Acidic slime is the perfect utility creature, an auto include in most green decks. Although creeping corrosion and bane of progress can set you back on mana, they're the bane of Nick's deck; no artifacts means no land destruction.

In general, i'd up the count on draw spells, counter spells, kill spells, (reality shift, pongify, and rapid hybridization are probably better than fight cards) add in other control spells like capsize and cyclonic rift, and really temper the creature section. Especially spend some time considering the balance between utility, versatility, and haymaker-quality; a good combination produces consistency, which is what you're ultimately going for. I hate to say it, but the best way to beat land destruction is to counter land destruction; this might end up as a control deck, first and foremost.

R.I.P. land destruction.

Nick, no hard feelings.