This doesn’t looks so simple to me. For starters, the chemical weapons will be well hidden by now. Even if they are located and destroyed with airstrikes, that would amount to their release at whatever location they were destroyed at.

Getting the units and chain of command that made the attack is also iffy (it assumes better information than we likely have, or likely ever will have).

My preferred fantasy scenario is a squad of death ninjas to assassinate Assad. Also unrealistic.