Interesting question. It is difficult to know exactly what he thought about the Soviets, because it probably changed over time.

First off, the Turkish War of National Liberation (or Independence) could not have been won without important financial and armament aid from the Soviets. Lenin also called Ataturk a “Muslim Communist”. Thus it was with Soviet gold and Soviet rifles that men fighting with the battle cry of “Allahu Ekber” won the Battle of Sakarya. So we can speak of a fundamental affinity between the USSR and Turkish Nationalists, which becomes especially poignant when considering that both groups considered themselves anti-imperialist viz a vi the Great Powers of Europe.

However, Ataturk was a nationalist and what might be called a third worldist later on— something that would get you gulaged pretty quick in the Soviet Union as “nationalism” was considered a reactionary petite bourgeois ideology. Notably, MirSultain Galiyev was purged from the Communist party for allegedly espousing such views.

Of course, Ataturk did not intend to win Turkish sovereignty only to hand it over to the USSR and many consider the Turkish Communist Party leader Mustafa Suphi’s disappearance over the Black Sea to be the work of Ataturk— though no evidence exists and shipwrecks can and did happen.

Ataturk and the Turks were clearly grateful to the USSR and Communists however, if you go to Taksim Square in Istanbul, the Monument of Independence depicts Ataturk flanked by Soviet Marshals and Generals.

So perhaps we can say there was a pragmatic affinity between Ataturk and Lenin or more broadly between the Turkish Nationalists and Soviet Communists. Turkey was economically organized like a communist country for years as well, with many large state owned enterprises and highly organized unions. Much of that was the legacy of Ataturk and a reaction to the memory of foreign-owned businesses in the late Ottoman period.

By the time Ataturk died, he was a model for both fascists and communists— a weird combo.

Many sources do actually confirm that Ataturk was in favor of State Socialism, what he liked to call "Socialisme D'etat". While it seems to true that he disapproved of the Soviet Union and Communism in general, he certainly was inclined to leftist economic ideas, which he then mostly implemented during his time as head of state (e.g. by state-owned and state-controlled businesses). On the other hand though, his nationalist political mindset is apparent and was a huge factor in maintaining his power. So to conclude, I would definitely say that he is somewhat of a Leftist Nationalist, which is somewhat confirmed due to the fact that his party, the CHP has become Turkey's largest Social Democratic party, which not only consists of Kemalists but also of Democratic Socialists and to a little extend even Communists