You have to:
Transfer it from the older DS Pokemon games or trade for it.
you can find it on route206
evolve nosepass. you can find nosepass in mt. coronet.
in granite cave use rock smash on the rocks until you find a nosepass if none appear exit the room then try again until u find a nosepass
in the poke transfer
You can find nosepass in granite cave very rare though.
Nosepass is a Rock type Pokemon that evolves into Probopass if it is leveled up in certain places. Wild Nosepass can be caught on Route 206 in Pokemon Diamond while they are swarming.
In granite cave.
You'll need to evolve from Nosepass, transfer Probopass, or trade for it.
In Granite Cave, there is a floor that has breakable rocks. Use Rock Smash on these rocks. You may find a few Geodudes, but you should find a Nosepass eventually.
You need to level it up in chargestone cave
You find it by the bike pass if you use the pokeradar.
in or on top of mt coronet