Can you describe the interaction between Sai Baba and Nana Chandorkar concerning a verse from the Gita?

Certainly. As detailed in Chapter 39, Sai Baba noticed his devotee, Nana Chandorkar, humming a verse. Baba intentionally asked Nana to recite it aloud and then explain its meaning in detail. The verse was from the Bhagavad Gita, specifically 4.34. Nana, being a learned expert in Gita commentaries, explained the conventional meaning: that one attains knowledge from the wise by prostrating, serving them, and asking respectful questions. This entire 'Sai-Nana dialogue' was orchestrated by Baba not because he lacked knowledge, but as a unique method to impress the true, deeper teaching upon Nana and all those present.