ONE question for a thread, please.
Your question should be on the topic.
Just "Beginner for Nios2" is not a good title.
1. Don't mix up Nios and Nios II.
They are almost totally different.
You should not work on Nios, unless you are maintaining an old product.
Yes, you can install the Nios2 binary toolchain from the wiki and develpe nios2 uclinux on Redhat 9.
But Redhat 9 is OBSOLETE. It is not maintained.
The some tools on Redhat 9 are old, and can not run buildroot.
2. jffs2 on kernel 2.4.22,
NO comment.
Nios2 uclinux use kernel 2.6 .