With steakhouses thriving again, Sizzler USA is planning to return to Illinois. The Culver City, Calif., chain expects to open 18 Chicago-area restaurants over the next five years, and hopes to recycle as many vacant units as possible. Only 179 of Sizzler’s original 700 outlets remain open. Chicago, once home to 15 stores, has been “Sizzler-less” for a decade. Sizzler also is eyeing expansion into Denver, Minneapolis and St. Louis.