So, I've already completed the Elite Four 5 times and the champion, and now I hear about Dexnav Chaining. I know that its not just for shinies but for IVS and im mainly going for shinies. Does anyone have a good tutorial on how to do this?
As usual Bulbapedia explains it pretty well:
Every time the player encounters a hidden Pokémon of any species for any reason, the chain increases. As the chain increases, the Pokémon have a greater chance of having any of the special attributes (IVs, eggmoves, hidden ability, higher level and item held).
The chance of encountering a Shiny Pokémon also increases, estimated to reach 0.5% per encounter after 40 chained encounters, and remain at that rate as long as the chain continues. There is thus a 50% chance of encountering a Shiny Pokémon in the first (roughly) 130 chained encounters.
A chain is broken when the player leaves the area (including entering a building), encounters a wild Pokémon that isn't hidden, or moves too quickly and scares away a hidden Pokémon. Hidden Pokémon can be encountered for a chain either with or without the Search function. Getting the message "The Pokémon couldn't be found. Try looking in a different area!" when using the Search function does not break the chain.
Here's a good video tutorial:
While in Pokemon X/Y you could chain encounters to increase the likelihood of running into shiny Pokemon, it appears that using the DexNav in Omega Ruby / Alpha Sapphire confers a flat bonus to your likelihood of running into shinies, regardless of how many encounters you've "chained".
So DexNav shiny chaining is not a thing. You do have a higher chance of running into shiny Pokemon if you use the DexNav, and it does appear that the shiny Pokemon encountered do have higher IVs if you chain encounters using DexNav, though.
Source: DexNav analysis on Reddit