You have the NE purchase permit and a NE state issued ID, nothing else is needed to buy a riifle, shotgun, handgun in NE.
For that kind of money I would recommend the Just Right Carbine in glock 9mm configuration. Or spend more money and get an AR platform in 9mm. The Taurus is a new product with an unknown track record and only has 10rnd mags available and those are not readily available.
The Taurus guns are in stock at multiple distributors which usually during these times of high demand for firearms means they are not selling well.
A rifle that takes Glock, M16, or UZI magazines is going to have plentiful spare magazines in full capacity available.