I was on my way to the sea and I saw a Breslov [Na Nach] fellow that goes around the main square in town with a shofar wakening people to repentance. I mentioned that I hold from and Gra and Rav Shach and he added that also the Chazon Ish, and Rav Kinyevsky [the Stipler and his son] and really all of the great Litvak sages learned the books of Rav Nahman.
And I definitely saw this myself when I was learning under the great Litvak sages of the Mir and Shar Yashuv in NY.
But they did not become "Breslov". They stayed Litvaks that go by the Gra by added to that the insights of Rav Nahman. There is a good reason for this but I have felt for a long time that it is not worth going into in public. In public, I only want to recommend Rav Nahman,- even though I realize that the ideas can be taken in wrong directions. You really need the Gra to stay steady on the straight path of Torah. Rav Nahman within that context can add a great deal