MIPS vs Nios II instruction

I presume you mean that you are trying to convert some MIPS asm source into a form that can be processed by the nios2 assembler?

The nios2 multiply and divide instructions put their results into normal registers - so there is no equivalent of %LO and %HI.

Also the divide instruction doesn't generate the remainder.

One approach would be to save the operands (esp of divide) and calcuate the value when it is needed. Register r2 is usable as a temporary, as is the actual destination register.

You might be able to save the values in memory relative to %gp. Possible alternatives are an alternate register set (usually used for interrupts) or some a custom instruction.

Another option is to re-implement multiply, divide and the read_hi/lo inside a custom instruction in a manner that matches the mips opcodes.