We thought we understood it. Xoco was Rick Bayless’ sandwich (torta) place next to Frontera and owned by him. Tortas Frontera was practically the same sandwiches, but a partnership with HMSHost to bring them to O’Hare (where they have rightly been regarded as a blessing from the gods). And Frontera Fresco was similar things in Macy’s. But now, with little fanfare other than a tweet from the man himself, a Tortas Frontera has popped up in the “Urban Market” food court in the Chase Building (better known for its old name First National Plaza). This is undoubtedly good news for Loop diners, even if it does mean somewhere, someone is wrestling with the choice of Xoco, Tortas Frontera or Frontera Fresco for lunch today.