As an amply nosed person myself, I can see many uses for this phrase.
This insult differs from most listed here in that it is actually intended as a compliment. Those familiar with the Song of Songs—by far the raunchiest book in the Bible—will have probably guessed this already. In “Solomon's Finest Song”, we hear the story of two young newlyweds, and, through a slew of variably comprehensible similes, we learn about their ardent admiration of one another—in this case, the young man’s appreciation of his ladylove’s capacious schnoz.
This nasal comparison comes amidst other comparisons between such things as hair and wild goats running down a mountain, teeth and freshly shawn sheep*, eyes and doves—we’ll leave aside the fawns and the grapes for now…
Unfortunately, (after a quick Google) it seems that no one really knows to which particular ancient tower the young groom was referring, or to its shape. We have our imaginations, though.
While I’m sure the young bride in the song understood the compliment and was sufficiently wooed, I’d love to see how well this comment would go down today.