Chemical Weapons vs Nuclear Weapons
Chemical Weapons and Nuclear Weapons are both destructive weapons. The world has seen the holocaust caused by nuclear weapons during the bombings on Nagasaki and Hiroshima during the 2nd World War. It was the first and last instance in human history that nuclear weapons were used. They caused massive destruction of lives and property and brought untold misery to the population because of radiation that continued even several decades. Nuclear weapons were the hegemony of only 5 countries in the world which were US, UK, Russia, China and France, but of later three more countries India, Pakistan and North Korea have become nuclear powers.
Chemical weapons include those arms that utilize deadly chemicals to cause death and harm to human population. Chemical weapons have been used for decades now but the world has now decided to rid itself of these weapons and their elimination from the face of the planet has already started. These weapons inflict untold misery upon the population on which they are used which is why the world has unanimously condemned their stockpiling and their elimination is a step towards world peace and stability.
Both nuclear weapons and chemical weapons are together (along with biological weapons) called Weapons of Mass Destruction (WMD). Both are deadly in so far as causing deaths and destruction is concerned, but where as nuclear weapons damage and destroy everything in their wake, chemical weapons are silent in nature as they contain poisonous gases that torture and kill life forms and vegetation. Nuclear weapons on the other hand release much more energy causing immense damage and loss of lives.
The world has been trying to control production and proliferation of these weapons, and since the signing of partial test ban treaty in 1963, considerable progress has been made through Nuclear Non Proliferation Treaty (NPT) and Comprehensive Test Ban Treaty (CTBT), though it is equally true that because of the biased nature of these treaties, three more nuclear powers have emerged in the process. However, the world has succeeded in controlling and eliminating chemical weapons which in itself is a considerable achievement.
Summary
Both chemical as well as nuclear weapons are called Weapons of mass destruction and bring misery to the population causing lots of deaths and destruction.
Realizing inherent dangers, the world is trying to contain and then eliminate these weapons and it has been successful as far as chemical weapons are concerned.