Advancing Care for Exceptional Kids Act of 2015 or the ACE Kids Act of 2015

Amends titles XIX (Medicaid) and XXI (Children's Health Insurance) (CHIP) of the Social Security Act to allow a state, at its option, to elect to provide medical assistance for items and services furnished to eligible children with medically complex conditions enrolled in a Medicaid Children's Care Coordination (MCCC) program.

Requires an MCCC program, among other things, to coordinate, integrate, and provide for the furnishing of the full range of MCCC program services to enrolled children, as well as designate pediatric care management services and pediatric focused care coordination and health promotion.

Requires a state to enroll eligible children prospectively in an MCCC program through an initial 90-day assignment to a nationally designated children's hospital network, unless the child opts not to participate in any MCCC program.