Wife sprayed with Empero nutsedge killer (comparable to Sedgehammer Plus, but a little cheaper through Amazon). Used twice and it works really well. Takes about 1-3 weeks to kill it.
Gotta say, was having a lot of nutsedge problems in our new sod. I was really diligent about going as far down as I could to grab it and pull it up everywhere I saw it. After a few weeks I haven't seen it anymore.