The NRST would be the only federal tax so your pay check would have no federal withholdings. State tax withholdings and state tax laws would remain unchanged.
"The NRST would be the only federal tax so your pay check would have no federal withholdings. State tax withholdings and state tax laws would remain unchanged."
That is very doubtful. Almost every state with an income tax piggy-backs onto the federal system. With no federal system to piggy-back onto, most states would drop their income taxes. Here in GA, there is already a bill in the GA general assembly to do that.
In all likelihood, most American workers would keep their entire paychecks - minus voluntary deductions such as health insurance, union dues, etc.