Which nation used "Suicide Squads' during the Second World War ?

Japan 🇯🇵. Kamikaze pilots during the Pearl Harbor attack.

Japan

US tank groups in Sherman's

You means Japanese

Kamikaze were a part of the Japanese Special Attack Units of military aviators who initiated suicide attacks for the Empire of Japan against Allied naval vessels in the closing stages of the Pacific campaign of World War II, designed to destroy warships more effectively than was possible with conventional air attacks. About 3,862 kamikaze pilots died during the war, and more than 7,000 naval personnel were killed by kamikaze attacks.[1]

Besides,Germany also use Hitlerjugend to carry suicide bomb to kill Russian during Battle of Berlin

China also had suicide squad against Japanese in second sino-japanese war

Pretty much everyone did.

The Japanese had the Special Attack Units (more commonly known as Kamikaze).

Germany and the USSR had the penal battalions which, while not officially suicide units, they would be sent to more active/dangerous parts of the front.

Britain and USA had the commandos, Rangers, Marine Raiders etc. Which were not strictly suicide units, but were often sent on missions where the chances of survival were slim.

Italy had it's combat divers/frogmen. Which again were not officially suicide units, but the nature of their work meant that chances of survival were slim.

Germany and the Soviet Union used penal battalions, serving in which meant that survival was unlikely.

Depending on how you define the term all of them.

Japanese -- Mini submarine operators, Kamikaze pilots, soldiers facing the disgrace of surrender.

Japan - kamikazes