Soil nails may be used to make the soil mass a "solid block" for bearing purposes, or may simply be a means to prevent sloughing. True soil nails are NOT really just a tie back for the wall that faces the cut, but provide restraint from movement and shear resistance to the soil mass.
I would not plan to excavate behind a soil nailed wall unless I had structural drawings for the building AND the wall was anything other than civil or architectural. If a structural wall stands alone, with a soil nailed, shotcrete wall behind it, I'd say it was temporary. If the soil nails are attached to the structural wall, the design probably requires them to be there.