Nathlekh is a city of Shou. This wasn't always the case, sometime back during the Spellplague, a disaster struck it, destroying almost all of it except for the district populated largely by Shou. The Shou rebuilt the city, aided by Shou migrants from surrounding lands, who flocked to the city. When they rebuilt the city, they made it their own.
In theory, it was stylised after Shou Lung, the empire from out east. However, most of the inhabitants had never been to Shou Lung; the city being made up of the descendants of those who had migrated from Shou long ago. As such, the city could be said to more closely resemble a Faerûnian's idea of Shou Lung than Shou Lung itself.
This is, of course, by design. The city presents itself as an oasis of eastern culture in an uncultured land. This, combined with the fact that they insist on limiting non-Shou to the outer city, means that it has an air of exclusivity. And, if there's anything that the wealthy merchants and lords of the Heartlands like to throw their money at, it's the right to experience something that others can't. Naturally, the walled inner city opens its doors to non-Shou willing and able to pay for the privilege.
Those who have visited the inner city speak highly of its “genuine” Shou cuisine; its luxurious spas; its mysterious fortune-tellers; its wondrous, “traditional” Shou magic and medicines; as well as half a dozen other things that may or may not have originate in Shou Lung.
Nathlekh paints itself as powerful and imperious. The city claims to be the capital of the mighty nation of “Nathlan”, but “Nathlan” seems to consists of naught but Nathlekh and a handful of surrounding farming villages. As for the wise and mysterious emperor, he has never been seen in public, if he even exists at all, as other rumours speak of a Council of Nine.
None of this really matters to most adventurers, though, who likely won't have enough coin to
get any further than the outer city. To those planning on sneaking into the inner city, the City of Cats is protected
by an elite group of weretigers. There are also rumours that the lion statues dotting the inner
city are capable of coming to life and attacking intruders of ill intent.