Could Nato defeat a alien invasion that is using 1940's tech?

8 giant saucers hovers in 8 different places on Earth(mostly in US and Europe. 4 in America: Washington DC, Los Angeles, New Orleans and New York. 4 in Europe: In Paris, London, Berlin and Madrid.

Each saucers has: 15 million soldiers. They will use WWII copycats of Nazi Germany weapons such as MP 40 machine gun, Panzerschreck rpg, Granatwerfer 42 mortar, german granate, MG-42 machine gun and 8.8 cm Flak for both artillery and anti-aircraft.

As for vehicles and aircrafts: 10 000 vehicles and 4000 aircrafts. Vehicles will be copycats of Tiger Tank II, Panzertank and Sd.Kfz. 251 half-track that has both machine gunners and 8.8 cm Flak artillery. Aircrafts will be modified Me-242 that carries 2 small rockets and equipped with machine guns.

The soldiers and vehicles will deployed by transport smaller saucers. This will be a alien blietzkrieg to attempt to overwhelm Nato. The aliens will wear totally black uniform similar to the SS, but with mask to cover their insectoid-humanoid faces. Their height are 6 feet and thin.

So question is: Can they do defeat Nato? Oh and Russia, China, Iran and N.Korea stays out of the fight because they want the aliens to destroy Nato lol

How quick can Nato respond? Are 15 million soldiers each cities too much for the national guards in America to take on?