Nebraska can act against both your driving privilege and your vehicle registration until financial responsibility is demonstrated. Paying the fine does not by itself satisfy that; a policy in force, and a filing where required, is what clears it.
More detail
Two separate things are happening. The citation is a court matter with a fine attached. The financial responsibility question is a DMV matter about whether you are insured, and it is the one that can reach your registration. Drivers who handle only the first are surprised when the second surfaces. The order that works is: get a policy in force immediately, because the gap is still growing and is being priced; read the DMV notice to see exactly what is affected and whether a filing is required; then deal with the court matter. One practical note on the citation itself: in some cases a driver who genuinely had coverage but could not produce proof at the roadside can address the citation by providing proof afterward, which is a question for the court that issued it.