Keyboard simulation with joystick (arduino uno)

So i want to make a nintendo 64 + snes controller and i dont know if i can simulate keyboard inputs with a joystick. is there any way i can do it? Thanks.

Yes, but you can't do it easily on an UNO. You need a board that supports USB keyboard emulation libraries, like the Pro Micro or Leonardo.

https://www.arduino.cc/reference/en/language/functions/usb/keyboard/
https://www.arduino.cc/reference/en/language/functions/usb/mouse/

So if i am not stupid mouse emulation is hard but just keyboard button emulation isn't as hard as mouse emulation. i am not going to need mouse it shouldnt be much of q problem(at least i hope so). Thanks a lot mate.

You're right, it's not a problem at all, provided your processor is a 32U4. The UNO doesn't have one, it has an ATMega328. That would be a big problem.