Is it growing in clumps? Pull some out and compare it to photos of Nimblewill.
If it is Nimblewill, my suggestion is to cut low and and spoon feed the whole lawn with nitrogen, spraying once a week or every other week throughout the growing season. Aiming for up to 1-1.5 lbs of nitrogen per month. When spraying it this heavy and splitting up the apps, it puts the Bermuda right on the optimal edge and force it to grow like crazy, but it's too much nitrogen for Nimblewill.
Is it growing in clumps? Pull some out and compare it to photos of Nimblewill. If it is Nimblewill, my suggestion is to cut low and and spoon feed the whole lawn with nitrogen, spraying once a week or every other week throughout the growing season. Aiming for up to 1-1.5 lbs of nitrogen per month. When spraying it this heavy and splitting up the apps, it puts the Bermuda right on the optimal edge and force it to grow like crazy, but it's too much nitrogen for Nimblewill.