When the oleo extends there is a two part block on the scissor and strut that locks the nosewheel in the "straight" position. The linkage from the rudder pedals is via a spring mechanism (there is no disconnect-too complicated and expensive and unreliable)and the springs compress when rudder is applied but the nosewheel does not turn due to the lock mechanism.
When sufficient pressure is applied to the nosewheel strut to compress it on landing the lock mechanism releases and the nosewheel is now steerable.
If the strut does not contain sufficient nitrogen pressure(flat is the term) it will not extend after takeoff and will not lock and if there is any rudder input on landing the nosewheel will be "cocked" and the landing will be "abnormal!"