I wanted to limit but not remove nukes and this might help..
It won't.
Increasing the number of Uranium needed will reduce the number of weapons you build before you run out of resources, which would reduce the number of nukes flying around, but there's so little Uranium in the game that you're effectively banning them outright for everyone other than that one civ that's conquered half the planet or settled unfavorable cities solely to get that extra Uranium deposit. And that's the civ you absolutely DON'T want having nukes; preventing smaller empires from getting nukes destroys the possibility of using them defensively (MAD), and makes it even easier to win militarily.
And if an AI does have enough uranium, it'll still build the nukes, and still use them as soon as possible. So it wouldn't change the underlying problem, which is the
use of the weapons; it'd just make it so that the first civ that faces an AI gets nuked but that they're not a threat after that. Right now you can already de-fang a nuclear power by bribing them to declare war on some other AI; the two sides will unload all of their nukes on each other, allowing you to roll over both with ease, although there's still a small threat of them making more nukes and hitting you. If you reduce the ability of the AI to stockpile, you make this even worse.
You can reduce the Flavor ratings to make the AI less likely to build nukes, but that wouldn't impact the player, and it wouldn't prevent the stockpiling issues.
As for the rest, I'd point to my own mod (Crazy Spatz's Alpha Centauri, which contrary to its name is not just a SMAC conversion), which has a working SDI project (actually two of them, long story). It also has some of the other things you've asked for (Mech Infantry are 42 in my mod, and Modern Armor do require both Oil and Aluminum, as do Stealth Bombers), but the nuke interception is what matters here.
Note that the existing Nuke Interception stubs in the XML do not work, so the SDI-type projects included in many mods don't actually DO anything. You have to code up explicit logic in Lua functions (mainly RunCombatSim) to handle interception, which on the bright side allows for some fun tweaking, like having A-bombs be easier to intercept than Nuclear Missiles, or allowing allies of the victim to help out with their own SDIs. I've got both of these in my mod.
This sort of nuke interception does limit nuclear warfare in practice, because an AI can't just unload its entire stockpile on the first turn of a war and end it then and there by gutting another nation. I mean, it CAN unload its arsenal, and still will, but if most of the atomic bombs are getting intercepted by SDI, then the defending civilization won't be utterly destroyed in the first wave. The ones that do get through will still do tremendous damage to units and tile improvements, so it'd still be in the AI's (and your) best interests to replace expended weapons ASAP. But it'd no longer be cost-effective to bribe AIs to nuke each other into oblivion.
