What steps can the UN Security Council take when a country tests nuclear missiles? It can ask the International Court of Justice for permission to impose economic sanctions, then intervene with peacekeeping troops.
It can pass a resolution condemning the action, then impose a series of economic sanctions against the offending country.
It can pass a resolution condemning the action, then ask the General Assembly for permission to overthrow the government.
It can send in troops to overthrow the government, then ask the International Military Tribunal to prosecute the leaders for war crimes.