EMB-145 Captain reported the nose steering locked up during taxi out resulting in having to be towed back to the gate for maintenance action.

Narrative

While taxiing onto the Runway XX for departure in Aircraft X; I made a left turn to align from the taxiway to the runway center line. As I neared the center-line the STEER INOP message populated on EICAS. I came to a stop and attempted to re-engage the steering. The message persisted. I advised my First Officer to notify the Tower that we've become disabled. An aircraft to the left of us on the taxiway stated that he could see our nose wheel and it was 90 degrees relative to the aircraft. He also stated that he saw it move some as well. I reattempted to re-engage the steering which yet there no changes. A QRH was completed but offered no help. We attempted numerous time to reach Operations. Then reached out to Dispatch via ACARS regarding the situation. We asked in that message to contact Operations via telephone. He also reported that he was unable to get an answer. ATC was again contacted and they sent an Airport Operations [Agent] to our ramp to alert them to the situation. I was later informed by the Ramp Manager that they were notified 'but were working another outbound flight at the time. I had informed her that our being disabled shut down the only runway available to the airport at the time. Additionally aircraft returned to their ramp as a result of ATC not having the runway available. At XA:46 a tow team arrived after pushing Aircraft Y flight and towed us back to the gate. We sat for over 30 minutes with Operations aware of us being disabled and need of assistance. Maintenance was contacted once at the gate and Contract Maintenance was dispatched at that time. A walk around inspection was conducted by both myself and my First Officer following our return to the gate. An emphasis towards HYD system 1 and nose wheel was also conducted. There were no signs of any abnormalities at that time. During the taxi out yesterday in Aircraft X at ZZZ1 from the RAMP the STEER INOP was also populated. The temperature was identical to here at that time (5 degrees). That turn was also to the left; but I was able to re-engage the steering during that incident and we experienced no additional abnormalities following that seemingly isolated incident.