In August 2011, seven people died and dozens were injured when a stage collapsed onto fans waiting for Sugarland to perform.
The state of Indiana promised $5 million (£3.22 million a the time) to victims of the accident, resulting in many people stepping forward, including two women who claimed fake injuries.
The families of the deceased and three injured audience members recently filed a lawsuit against the firm Mid-America, which built the rigging and roof that caved in.
According to WENN, Nettles has now been asked to testify because Indiana State Fair Commission Executive Director Cindy Hoye maintained during a deposition earlier this year that Sugarland refused to postpone their show despite severe weather warnings.
Nettles's bandmate Kristian Bush will not have to testify.
Watch Sugarland remembering the victims of the stage collapse below: