It seems that Nash had a deficiency exposed while at the Slade: he wasn't very good at depicting people. As a result, he generally painted landscapes. During the 1930s when Surrealism became fashionable, he did works in that vein based on landscape art.
Nash is best known as a war artist, particularly for his works featuring the Great War (he also depicted World War 2). Unlike many men commissioned to do war art, Nash had had combat experience as an officer and knew full well what that war was like.
A 1917 exhibit of works dealing with Ypres led to his posting as a war artist, according to the Tate link above. This painting was done later.
Showing why Nash seldom featured people in his paintings.
This and the Ypres Salient painting above are probably his best-known Great War paintings.
A nice, bold composition, which accounts for the tilted horizon line, I suppose.
An early Surrealist work.
Much Surrealism supposedly dealt with dreams, something I find hard to believe.
Nash wasn't any better with airplanes than he was with people.
Perhaps his best-known Second War painting.
This painting is dreadful. Perhaps Nash's frail health was overtaking his abilities.