A319 Captain reported loss of nosewheel steering and braking issues during landing roll due to a hydraulic leak.

Narrative

During landing rollout; we received a HYD G RSVR LO LVL message at about 70 kts. We transferred aircraft control and I steered the airplane off the runway using rudder control at taxiway 1. The tower controller informed us to take [taxiway] 1 and 2; so we rolled onto 2. The first officer started the ECAM procedure while I taxied. It quickly became apparent that we didn't have nosewheel steering and our brakes didn't feel right; so I stopped on taxiway 2. We finished the ECAM procedure and verified that we didn't have nosewheel steering; so we informed the tower controller that we were disabled and would need to be towed in to the gate. The tower controller directed several inbound aircraft to go around; as we were blocking the only open taxiway between [Runway] XXL and the terminal; while we arranged to be towed to the gate. Some safety vehicles payed us a courtesy visit and informed us that we had a large puddle of hydraulic fluid under the engine; so we shut down the engines while we waited for the tug. After that we got towed to gate without incident.Cause: The corrective action in the AML reported that mechanics found Line #XX on the LH MLG to be leaking. This was not noticed during pre-flight walk around inspection or before start flow (ECAM check).