just give them water, pH´ed. they should be fine unless you overdid it badly. it happens, no worries.
now if you dumped the entire jug of nutrients on 1 plant, you might wanna flush, but if its just minor toxicity, then dont worry, just water it next time, with no nutes (maybe still micro nutes). if you know you added too much N, then water with everything but N next time. get what im saying?