01 Nissan Maxima Motor mounts need to be replaced 4 months after car was rear-ended Could the accident cause?

Yes, The impact from the collision may have caused the original motor mounts to shift, weaken or even bend, accelerating their deterioration and eventual failure. Additionally, the car frame can be shifted that can alter the car's alignment, also putting an additional strain on the motor mounts and leading to premature failure. It's important to inspect the car for any other damage that may have been caused by the accident.