Well, if you consider a chile en nogada a chile relleno (which you must because it certainly is by any "stuffed pepper" definition), then it's worth the effort to track some down. They're seasonal, around Mexico's Independence Day, because the unripe walnuts traditionally used in the sauce are available then along with pomegranates (which were less universally-available not long ago) and because the uncoated poblano chile, white sauce, and pomegranate seeds invoke the Mexican flag. They're stuffed with a meat, nut, and fruit mixture. Maybe best not to let me get started since they're my favorite food - I'll get them from a different place every day in season.
Cielito Lindo has a pretty decent one year-round. The sauce makes concessions to the unobtainability of unripe walnuts most of the year but is still good, and they have a distressing tendency to sprinkle them with guava seeds (which are much worse than they sound in this dish, and have large, rock-hard seeds), but I like them. The biggest problem at Cielito Lindo is that they also usually have chamorro, and how do you pick between that and chile en nogada?!?
