i understand that a while ago UEF nano was deemed too OP, and nerfed. It previously costed significantly more, but gave 200HP/s regeneration. This rendered it immune to the damage of 1 Guncom or ~6 T1 tanks.
As it stands, Nano gives +60 hp/s regeneration.
For its cost, this is insufficient and enough to render it a "useless" upgrade, when considering the other upgrade on this slot, T2 gives +20 hp/s regeneration and 3K health. And that 3K health bonus makes ALL the difference.
Testing 2 UEF guncoms against each other, one with nano, one with T2, they mutually annihilate (by gunshot, not by explosion damage) However, Nano costs more. Alot more (especially power wise, but also ~2x the mass), with T2 one also has the advantage of having the extra buildpower, the ability to build shields, flak, radar etc, spam T1 pd... etc, and later on upgrade to T3, T2 is undoubtedly the ONLY choice.
Now, this was of course in a single engagement with a single enemy of equal firepower however that was simply the reference. Nano would come out ontop in a protracted battle with breaks inbetween to allow for regeneration. However, still, in direct firefight, for a significantly greater cost, Nano provides the same survivability vs a single guncom (actually less as the amount of firepower on you increases)
Given that there is a tradeoff in effectiveness between regeneration and healthpool to regenerate, id seriously suggest not necessarily that nano should give greater regen, but that it should give a healthboost +2K would allow it to survive a direct engagement with a T2 guncom if there is a ~10-12s lull where the acu can regenerate, again as more firepower is brought to bear on a nanocom this advantage diminishes. (to provide the same survivability in a single engagement without the health boost, the regen would have to be 93, rendering it nearly immune to a stock ACU, which was the problem with the high regen in the first place)
Currently, there must be at least a 1 Minute break in fighting where the nano acu is allowed to regenerate untouched for it to even emerge victorious (at almost 0 hp) against its T2 brother.
As the close-range deathnuke does 2.5K dmg, the outcome will be the same vs any other race's T2/Gun
Given that you already pay heavily by not having a T2 engineering suite i'd say this might make nano at least a decent option in a niche battlecom scenario, rather than being no option at all.
I wouldn't say this is a serious issue, however, i do think the upgrade was nerfed TOO hard (the reduction in price did not equal its reduction in effectiveness), and it just pains me a bit to see the option for it there, and knowing it's inferior to a significantly cheaper choice.