Hi,
You can simulation NIOS II processor. Follow the steps as mentioned in application note in link below.
It provides with an example design along with the reference to relevant document.
https://www.intel.com/content/www/us/en/programmable/support/support-resources/design-examples/intellectual-property/embedded/nios-ii/exm-simulating-niosii.html
You may refer to youtube how to video on same topic.
https://www.youtube.com/watch?v=Jw3rr76QEIc
Thanks,
Arslan
