Thanks Red_Devil 232
I see where Scott’s recommends: Ortho® Weed B Gon MAX® Weed Killer For Lawns Ready-Spray
It kills chickweed and 250 others without hurting the lawn.
That is what I would try. Just be patient with expecting immediate results. Round up will do the job but kill everything else. Most people think when they use Round Up the offending plant will die the next day. It can take a couple of weeks for it to do its job completely. It will work.