When the Portland Timbers play Orlando City in the MLS is Back tournament championship on Tuesday night, assistant referee Kathryn Nesbitt will become the first woman to work a Major League Soccer title game.Nesbitt and Felisha Mariscal are the only two women among more than 40 officials that have been sequestered — just like the teams — in Florida for the monthlong tournament.“We all came into this tournament under really unusual circumstances,” Nesbitt said. “I think that the entire referee group here worked incredibly hard to have strong performances and to be named to the final means that you’ve had a strong performance and really shown what you’re worth here.