The nation's tata is simply a slang term for a breast that, although it may be a bit
on the small, or perhaps overly large side, is still leaning towards average. You might say that a breast that is the nation's tata is still easily
squeezable,
played with, etc.
Although my chest isn't that big, I'm still nation's tata.
Although I
surprisingly wish I was a bit smaller in
the chest area, I'm still nation's tata, so
it's not that much of a problem.