The problem is that 1/3 of Soviet Army is too much for Ukraine even with reasonably prosperous economy. It would probably ruin said economy anyway. They could retain Black Sea Fleet by being more stubborn to Russian demands. But again, they would not have much use for it except to sell piecemeal or wholesale until reduced to reasonable levels. Main benefit would be to deny Russians one, but at the time relations were not
that hostile.
Full military is unlikely as many officers and soldiers were not from Ukraine. And 2% of total population serving in the military in the peacetime is bordering North Korea.
Nukes decay with time, they need service and replacement. Very costly ones. I doubt than Ukraine has or had full production circle.
So unless Ukraine wanted to use that military immediately (Ukraine Empire TL

, there was no real point clinging to it. In fact, what they had was entirely sufficient to ward against anything short of US. Sure, a few nukes on starting positions may prove useful against Darth Vlad, but so is fully functional and equipped army Ukraine should have possessed OTL.