The lack of (28mm) Regular infantry for both Nationalists and Republicans is my pet peeve.
To answer you question; frankly, no. Not really.
The most distinguishing mark for Nationalist infantry, especially in the first two years of the conflict, would be the granadero flared trousers, and I feel that at least 50-70% of them should wear the guerrero tunic and gorilla side cap.
You could use the Empress Falangists, suitably painted, to represent Nationalist regulars in shirt sleeves. Empress also sells separate heads so if you substitute the gorillo heads with helmeted ones, some more variation is possible.