Nios II runs Hello world by chance

The words above are printed by the nios2-terminal host application when it starts up - they do not come from the nios2 processor.

I would start by checking that your clock is running, that your reset drives at the correct time and is not stuck asserted and that you are getting no critical warnings from the timing analyser.

Once you've done that check the output from `jtagconfig -n` contains a Nios II processor and check what nios2-download says about it.