NIOS II:Debug without the target

Is it possible to debug the Nios II SW without the physical board where my project will fit?

I mean I can substitute all input and output with a Jtag (using Signals & Probes) or with a VHDL block that generate my input (sometimes I use it in FPGA for debug purpouse), but if I've a Nios in the board I need to test my SW and expecially in the beginning I'll have not the physical board for myself...

So.. is there a way to debug Nios II SW without the target or I need to have it?

Thanks in advice