Germany has had hundred thousands of tons of Chemical weapons and many production facilities to produce them.
Among this, more than 12.000 tons of Tabun, more than 30 tons of Sarin and little amounts of Soman. I think, this is more than enough for everything what you want to finish... They have had also the granates and the bombs to deliver them. They have had also more than enough Lost, Clark I, Clark II, Adamasit, Phosgen, Zyklon B and and and...
Let say it on this way. With Tabun, bombs and cases to deliver them and the AR 234 or the V2 (I'm not sure, but I remember to heared/read, they have had warheads to deliver Tabun with the V2), Germany has had the the stuff to less or more finish every enemy town in europe.
After WW2 the allied forces stored much of the chemical weapons (under it with Tabun filled granates and bombs) on several ships (like the Leipzig) and sunk them mainly in the baltic sea but also in the northsea.
I would just say, Germany didn't need to develope the A-bomb.
Also the allied forces didn't need them in WW2.
The Royal Air force over Germany and US-Air Force over Japan prooved several times that it is possible to wipe out a whole town just with convential weapons (firestorm), just think of Dresden, Hamburg and several japanese towns.
It sounds to be unbelievable but it has been shown, that AH was not willed to use chemical weapons in WW2.
It is known, that Bormann, Goebbels and Ley tried to force him to allow the use of Tabun.
There could be several reasons, why AH was not willed to use them.
1. He was wounded by gas in WW1.
2. The germans feared, the allied would have something comparable (we now know, they didn't).
3. There was no drug to heal there own with Tabun or something comparable wounded soldiers (Atropin).
4. The germans believed the allied forces knew of the german gas program. Now we knew they didn't know anything.
5. Because of the typical wind direction, gas weapons were not realy useful against allied western forces.
I'm think, if the allied forces would have used a A-bomb against a german town...
Germany would have answered with Tabun against a allied town.
In my opinion, if someone uses a weapon of mass destruction against you (especially against civilians), you are allowed to answer with weapons of mass destruction.
I think, germany would have send an horrorfiing answer.