I guess I should tell you why I would not weld nut on . 1st a nut has grades of hardness 2nd a nut deforms when welding so often times you deform the threads and hole so you have to use a bottom tap to clean threads but now you've hardened nut and your taping a blind hole , its easier to use cold roll or piece of mild steel then drill thru and tap after welding and yes a mig will do the work you need no need for tig