Multiple Nios2 cores inside an FPGA?

There was another similar question a few days ago...

The advantage of SoC systems (and hard cpu on fpga) is that the cpu will run considerably faster than a Nios.

OTOH the Nios is more flexible especially if you are integrating with other bespoke logic on the fpga.

One of the reasons we've moved a lot of stuff into fpga is that they don't go obsolete in the same way as other components.

Although the fpga itself might be obsoleted, a newer part will typically do the job and require limited rework rather than a complete redesign.