I started having game night every month at my house, and typically we play Nintendo games like mario kart, smash etc. But i would like to change it up and  was wondering if anyone had recommendations fo local-multiplayer games, whether they be psn games or retail.

Jack's Party Box or whatever it's called. I think it supports up to 8 players using their smart phones or tablets. Has games like Drawful and stuff.

You could try 4-player local Borderlands 2/Pre Sequel?

does look like there'd be a tun of laughs there. 

Shadow of the Colossus. That's a fun party game. Just pass the controller around!

Lovers in a Dangerous Spacetime is pretty rad with 4P :

https://www.youtube.com/watch?v=Nhtc6fhw1YY

looks fun, I'll add that to the list to consider.

I heard Rocket League is pretty cool.

https://www.youtube.com/watch?v=TQSpBZRVIUM

Trials Fusion - each player chooses what they would like to race each other with: beginner bike, dirt bike, trials bike, peddle bike, pit bike, 4-wheeler, or a unicorn. Then race each other to the finish line.

I've made a couple local multiplayer tracks in it already that can be downloaded and played with your couch co-op buddies already. Otherwise there is a whole slew of ones that the game naturally supplies you with.

I play a lot of local 4 player coops (with my kids and my brother), so here are few non-Nintendo games that we enjoy:

Overcooked
Helldivers
Gauntlet
Rayman Legends
Little big Planet 3
Lara Croft and the Temple of Osiris
Tiny Brains
Lovers in Dangerous Spacetime
Moonhunters
Hammerwatch

For more games, I highly recommend this site:

http://www.co-optimus.com/system/22/playstation-4.html

Helldivers. Best coop top down shooter.