Parents and guardians of more than 1,200 disabled or chronically ill children got the go-ahead this week to jointly pursue the accusation that the state of Illinois is violating the Medicaid Act.In a written opinion Tuesday, U.S. District Judge Charles P. Kocoras certified a class of plaintiffs in a lawsuit alleging the Illinois Department of Healthcare and Family Services is running afoul of the law by failing to provide promised in-home nursing care.The class includes children who have been approved to receive EPSDT …