Competition in the Tex-Mex and Mexican segments of the restaurant space has been fierce in recent years, led by fast-food chains Yum Brands' Taco Bell (YUM) and Chipotle (CMG) . Taco Bell is king with about 7,936 locations in the U.S., according to data company ScrapeHero. Chipotle has a good size of the market with 3,398 units. Other major players include Qdoba with over 750 locations and Del Taco (TACO) with over 600. Certain Mexican casual restaurant chains have had financial difficulties trying to compete and needed to file for bankruptcy. Chevy's Fresh Mex, which had as many as 37...