On the Nationalist side, most of the foreign support came from Germany and Italy. Both supplied planes for the airlift of the Army of Africa to the Spanish mainland very early on in the war, giving the Nationalists an early advantage. Germany supplied the Condor Legion, which is best known for its aerial contingent but also included an army portion as well--10,000 total men at any one time. Equipment was weighted towards aircraft, with some 600 planes and 200 tanks. The Italians supplied the Aviazione Legionaria and the Corpo Truppe Volontarie, respectively an air force and an army contingent. In numbers, the Italian force dwarfed the German one, with 50,000 men serving. In equipment the Italians supplied roughly similar numbers to Germany, but most of these were slightly inferior to the German equivalents (tankettes instead of tanks, and Italian aircraft had some good examples but Italy had difficulty supplying them in bulk). These were technically "volunteer" formations, a legal fiction so that Italy and Germany could maintain their official policy of "nonintervention." Portugal supplied some men and weapons on a smaller scale, and other nations had volunteers for the Nationalists. Other companies--particularly in the US--sold equipment to the Nationalists such as trucks.

On the Republican side, the Soviet Union supplied the largest amount of war material, with some 600+ planes and over a thousand tanks. Less than a thousand Soviet men at any time were in Spain, though. The International Brigades were volunteers for the Republic, with roughly 40,000 of them serving. Mexico supplied tens of thousands of rifles and millions of rounds of ammunition. French aid was small due to their official policy of nonintervention (a smattering of aircraft), and British aid was even smaller (mostly volunteers).

That's a very rough sketch. Antony Beevor covers this in good detail in his book The Battle for Spain.

As always, followup questions from OP and others are encouraged.

What kind of tanks and planes did each side receive