A disabled former construction worker who said he was denied automobile liability insurance despite a good driving record and solely on account of his handicap is the principal plaintiff in a multimillion-dollar class-action suit filed against 20th Century Insurance Co. The Los Angeles Superior Court suit alleges that Dennis Nutter and a class of other “aggrieved and potentially aggrieved persons (were) discriminated against . . . solely because they are physically handicapped,” in violation of California insurance laws. Attorney Dan Stormer said Nutter, a Silver Lake resident who suffered hip and back injuries in an industrial accident several years ago, is able to drive a car and has a good driving record, even though he is unable to work. The suit asks for $4 million in punitive damages for Nutter and $100 for each of the people in the class action. A spokesman for the Woodland Hills-based insurance company said he had not seen the suit and therefore could not comment.