diff --git a/generate/generate.go b/generate/generate.go
index ae5a9984..140ba4f5 100644
--- a/generate/generate.go
+++ b/generate/generate.go
@@ -540,6 +540,9 @@ func (g *Generator) addEnv(env, key string) {
 	} else {
 		// else the env doesn't exist, so add it and add it's index to g.envMap
 		g.Config.Process.Env = append(g.Config.Process.Env, env)
+		if g.envMap == nil {
+			g.envMap = map[string]int{}
+		}
 		g.envMap[key] = len(g.Config.Process.Env) - 1
 	}
 }
diff --git a/generate/generate_test.go b/generate/generate_test.go
index b27dc3fc..ea8f188a 100644
--- a/generate/generate_test.go
+++ b/generate/generate_test.go
@@ -124,6 +124,12 @@ func TestEnvCaching(t *testing.T) {
 	}
 	g.AddProcessEnv("", "")
 	assert.Equal(t, []string(nil), g.Config.Process.Env)
+
+	// Test with nil envMap.
+	g = generate.Generator{}
+	expected = []string{"k1=v1"}
+	g.AddProcessEnv("k1", "v1")
+	assert.Equal(t, expected, g.Config.Process.Env)
 }
 
 func TestMultipleEnvCaching(t *testing.T) {