You can, but understand how nosummon works first. You WILL take damage. The way it works is that the plug-in recognizes when you have been summoned and warps you back to your previous location. So you can expect to take an attack round or 2 from the boss on each summon depending on latency.
it’s still very effective and much better than the standard summon tanking of backing out.
also, it’s important to be a decent distance away, sometimes if you are to close, nosummon fails to warp you out.