Air carrier Captain reported encountering surface conditions that led to NIL braking action resulting in loss of control of the aircraft during taxi. The aircraft came to a stop on the taxiway and they coordinated with airport operations for recovery.

Narrative

During taxi out to departure we encountered surface conditions that led to braking action becoming NIL and complete loss of directional control. Over the course of approximately 20 seconds the aircraft slid to stop while it weathervaned into the 11 kt crosswind. At no point did the aircraft leave the paved surface; nor did any part of the aircraft make abnormal contact with the surface.We had briefed the taxiway conditions considering the NOTAMs and discussed the need for two engine taxi; cowl anti-ice selected on; and at no more than a walking pace. After a normal engine start and power out we commenced taxi. We taxied at two engine idle thrust and slowly; with aircraft taxi speed responding normally to brake pedal pressure. Our ramp weight was around 60;000 lbs. About 2/3 through the taxi operation the aircraft began to gain speed without having relaxed pedal pressure. Indeed as I increased pedal pressure to slow the aircraft there was no detectable deceleration. Simultaneously the aircraft began to yaw into the wind. Yaw control was unresponsive to both tiller movement and rudder input. I held the brakes until the aircraft came to a stop. We stopped almost completely perpendicular to the taxiway. Passengers and cabin crew were unaware that we had lost control as it was so gentle and drawn out. The brake was set; we started the APU; shut down engines; contacted with the FA (Flight Attendant) and informed the passengers and began coordinating a recovery plan with Airport Ops and Station Ops.Cause: The airport operations did not accurately report field conditions.The relevant FICON (Field Conditions) NOTAM for airport surfaces at the time of release read as follows:TWY ALL FICON PATCHY COMPACTED SN AND PATCHY 1/8IN WET SN PLOWED 45FT WID REMAINDER 8IN DRY SN OVER COMPACTED SN OBS AT XXXXXXXXX-XXXXXXXXXX.The flight operated about 90 minutes after the NOTAM was issued.After our loss of control event; airport operations updated the NOTAM as follows:TWY ALL FICON WET ICE AND PATCHY COMPACTED SN SANDED 45FT WID REMAINDER 8IN DRY SN OVER COMPACTED SN OBS AT XXXXXXXXXX. XXXXXXXXXX-XXXXXXXXXX.Wet Ice as described in the updated NOTAM is in fact the conditions we encountered and corresponds with braking action NIL on the RCAM / Braking Action Table. The RCAM / Braking Action Table describes deceleration and directional control observation as; 'Braking deceleration is minimal to non-existent for the wheel braking effort applied OR directional control is uncertain.'I think that the FICON NOTAM at the time was cut/paste from a previous observation the day prior.Airport Operations should do better to accurately assess and describe field conditions in their NOTAMs; or they close taxiways entirely if they are unable to assess field conditions in a timely and accurate manner.Consideration should be given in our SOP to utilize back-taxi at non-towered airports where airport Ops has been treating the runway surface; but neglecting to treat the taxiway surfaces.