Question

Will shiny Pokemon appear in the Dex-Nav?
Also will it increase your chances of getting a shiny like the Poke-Rader?

Answer 1

Yes, Dex Nav is a shiny hunting method that gives you vastly increased shiny odds. The odds vary immensely based on your search level and if you have the shiny charm or not, but they sit around 1/512 and can go up to as far as 1/200.

Per Bulbapedia:

There is a small chance a Hidden Pokémon may be forced to be Shiny.

The game performs a special calculation to determine if a hidden Pokémon will be forced to be Shiny. This algorithm primarily depends on the Pokémon's Search Level, but may also be influenced by other factors. Note that even if the game does not force a hidden Pokémon to be Shiny, it may still naturally end up Shiny.

To check if a hidden Pokémon will be forced to be Shiny, the game compares a target value with a random number from 0 to 9,999, and if the random value is less than the target value, it will be Shiny. The target value depends on the Pokémon's Search Level. ... The chance of forcing a Shiny Pokémon starts at a miniscule 1/10000 of 6% at Search Level 1, and it increases by 0.01% after every 16 2/3 Search Levels up to 100 (reaching 0.06% at Search Level 100), after every 50 Search Levels up to 200 (reaching 0.08% at Search Level 200), and after every 100 Search Levels thereafter. By comparison, the natural chance of finding a Shiny Pokémon is approximately 0.024%; the chance to force a Shiny Pokémon only exceeds this after Search Level 40.

Answer 2

Yes Shiny pokes can show up if you use the Dexnav, I got a shiny maril using it. idk if it increases the chance or not, but I'm pretty sure they increased the encounter rate overall cuz ive played the game for 80 hours and 38 mins and already have 2 shinys not including the beldum