There's a local chain here in the 'Nati called Izzy's. They make a reuben comparable to Katzs or Eisenbergs in NYC. Was started in 1901 by a dude named Izzy Kadetz, a Jewish immigrant who moved here and opened the first kosher deli West of the Alleghenies. Sandwiches are great, but they make a deep fried potato pancake as big as your head that's amazing. Apparently the dude was like the Soup Nazi. He constantly insulted, ripped on, and made fun of patrons all the time. In the 20's people used to line up around the block at lunch for the grub, and the hope that Izzy would put them down, so they could tell all their friends. People are weird.
We also have a chain called Penn Station East Coast Subs that makes a nice steak. Kind of like Great Steak and Fry, only better.
Also, a place called Tom+Chee. They used to sell tomato soup, and grilled cheese sandwiches from a food cart downtown. People went crazy for it. They went on Shark Tank, expanded their sandwich menu, and now are in about a dozen states and growing.
As for larger chains, Panera is pretty decent. So is McCalisters.
When I lived in DC full time we used to go to Mangialardo's. Amazing Italian subs.
Bub and Pops makes great hoagies too.