nukes and chemical weapons can only be bought or sold via direct trades, that is from the "trade" menu you'll find trade directly
nukes and chemical weapons, wmd, their are 2 ways to get them. build your own strat, and pluto corps, then either contract directly to your self, or occasionally manually sell to your self, (you'll find these options near the bottom of the corp page.) the other way of obtaining them... find some one that builds allot of them, and talk them into selling to you
you will not be able to buy wmd from the open market, thats normal. you must either build them your self, or get another player to sell them directly to you.