Fair performance comparison betweem LMS & NLMS
For fair comparison of one algorithm to another, the value of step size does not need to be same. You can adjust the step sizes of both algorithm so that the mean-squared-error learning curves base floor gets same and in this way you will be able to differentiate the performance of algorithm. For base floor I mean the value at which the mean squared error curves coincides with each other at the end of iterations or data samples. You can adjust the step size by hit and trial method.