Air carrier Captain reported aircraft experienced an uncommanded slide while on an icy taxiway at ORD resulting in momentary loss of aircraft control.

Narrative

In ORD taxiing in from landing on 27R. We got taxi instructions to turn onto TT and hold short of 27C. While coming up to the turn I slowed down pretty far from the turn because I knew it was slick and icy. As we came up to the turn ATC told us to cross 27C and hold short of 27R on TT. As I made the 90 degree Right turn onto TT from taxiway D I had slowed to the appropriate speed and then applied power to make the turn. During the turn as I straightened out the nose wheel it abruptly became apparent that the turn was not stopping and the nose wheel was continuing to slide right. I did whatever I could to stop the aircraft immediately. The taxiway felt very icy because even at the slow speed we were; the plane was not stopping quickly. We came to a stop and advised ATC of the situation because we did not know where the aircraft orientation was. So we needed help in which my FO called ops for a tug team and advised ATC that we needed a tow and that we were just past the hold short line of 27C. The move team and maintenance came out to the aircraft and accessed the situation. They notified me that the aircraft was still on the pavement and that there was no damage to the aircraft nor ground equipment. The move team was able to attach a tug and pull us to the left back to the middle of the taxiway. We were then able to taxi to the gate under our own power.