Replacing kitchen facet - nut stuck

I attempted to replace my facet when I was replacing the garbage disposal. Garbage disposal was easy not so for the kitchen facet. One side of the facet I could get a deep well socket which was easy. The other side has the sprayer hose with a large threaded hole and large nut. I tried spraying with WD40, I tried channel locks, I tried vise grips, I tried a crescent wrench nothing would budge it. I didn't want to totally trash it so I ended up just putting everything back together figuring I'll try later. Anyone have any suggestions?