Estimated Income Tax Payments and Penalty for Underpayment of Estimated Income Tax.
You may owe a penalty if your estimated income tax payments did not total at least:
90% of the tax shown on your 2021 Nebraska return; or
100% of the tax shown on your 2020 return; or
110% of the tax shown on your 2020 return if AGI on the return was more than $150,000; or, if your filing status is married, filing separately, more than $75,000.
See the Individual Underpayment of Estimated Tax, Form 2210N, instructions.