Nimzowitsch's chess theories flew in the face of convention. He had a lengthy and somewhat bitter conflict with Siegbert Tarrasch over which ideas constituted proper chess play. While Tarrasch refined the classical approach of Wilhelm Steinitz, that the center had to be controlled and occupied by pawns, Nimzowitsch shattered these dogmatic assumptions, and proposed the controlling of the center with pieces from afar. In this way, the opponent is invited to occupy the center with pawns which thus become the targets of attack. This idea became known as the hypermodern school of chess thought.

Nimzowitsch, along with other hypermodern thinkers such as Richard Reti, revolutionized chess, proving to the chess world that controlling the center of the board mattered more than actually occupying it. Nimzowitsch is also a highly-regarded chess writer, most famously for the 1925 classic My System, to this day regarded as one of the most important chess books of all time. Other books include Chess Praxis which further expounds the hypermodern idea, and the seminal work The Blockade explores the strategy implied by his famous maxim, "First restrain, then blockade, finally destroy!"

As a profound opening theoretician, Nimzowitsch has left a legacy of variations, many of which are still popular today. The Nimzo-Indian Defense (1.d4 f6 2.c4 e6 3.c3 b4) is named after him, as are several variations of the French Defense. He also is credited in part for the Sicilian, Nimzovich-Rubinstein (B29) Variation (1.e4 c5 2.f3 f6), the Nimzovich-Larsen Attack (A01) (1.b3), the Nimzowitsch Defense (1.e4 c6), and many others.