[Coda]

That said, you may be getting "nan da tte" mixed up with it. This is "nan da" (casual form of "nani desu") which means "what is it?" plus tte for emphasis.

This "tte" can also be said or written as "to" (which is technically more formal) and it's the same tte/to that you hear in phrases like "___ tte nan desu ka?" ("what is ___?", polite) or "___ to moushimasu" ("I am called ___", formal) and functions vaguely like a verbal quotation mark, although it's hard to really explain.

Edit: And don't confuse "da tte" with "datte"; they're two different things. :P