Welcome to Theorytron, Today we will be explaining who is the strongest Nick. Oh, and No Sonic Fanon Nick, because obvious is obvious.
So, let's start the scaling.
Nick's DETERMINATION exceeds most other Nick's DETERMINATION (except for sonic Nick). If Nick has enough DETERMINATION, he could possibly bust a Planet at best, not impressive I know, but Nick would be harder to KILL, since you know DETERMINATION, so he has that going for him.
Fairy Tail Nick
Fairy Tail Nick is the Lightning Dragon Slayer which gives him a HUGE edge as he can eat Electricity, Static, Bolt, Lightning, pick your poison, so Zelda Nick, Mario Nick (with Lightning Flower) and Neo Reality Nick are basically gas tanks for him. He also has lots of techniques, which gives him another slight edge, he might destroy a solar system if he isn't careful.
Mario Nick is, to put it bluntly, The weakest. He is a Human, and has no DETERMINATION like Undertale Nick, his weapons and items are the only thing going for him, mainly his Golden Flower, Starman and Mega Mushroom. He might be able to at best, destroy a country.
Legend of Zelda Nick
Zelda Nick is stronger than most because of is gear and experience. He can control lightning and is immune to all lightning but his own... or anything that hits his face *shows him getting zapped because he has no mask* But that doesn't mean he's necessarily vulnerable, he would be too careful to protect his face and hack and slash the enemies, He could possibly destroy a solar system.
Remember how I said Mario Nick is the weakest? NOPE! Pokemon Nick is a human with NOTHING. This is a fight between Nick's, with no interference, what does that mean for Pokemon Nick? No Pokemon. He could only destroy a large rock if he got mad.
Neo Reality Nick
Neo Reality Nick is one of the strongest of the Nick's because of his Level and Items. His Sword is strong enough to destroy a planet on it's own. His Electromancy/Electrokinesis might be very effective, but it could take out a few Nick's. He could destroy a Galaxy at best with his strongest technique.
Dragon Ball Z Nick
Alright, now we're getting into the good stuff. Z Nick can already blow up caves and buildings and planets without trying, but with the Kaioken attack, can destroy a Galaxy with the x20, with ease. Easily one of the strongest, his techniques are varied giving him an advantage. With his strongest technique (Super Burst Bomb) and Strongest Transformation (Kaioken x20) He could destroy a universe.
Mega Man Nick
Mega Man Nick may not seem like he has much, and he doesn't. But his power drives give him an advantage and his Arm Cannon, Energy Shield and Energy Sword can help alot. with the Power Drives, he could with his strongest technique, destroy a galaxy.
Alright, that's all of them, what, you wanted a discussion after that? SUCKIE, WE HAVING A FIGHT UP IN THIS BUISNESS!