I am thinking of changing my hotel booking to Shamrock hotel along Nathan Road, Hong Kong.

Yes, take shuttle bus line A21 and get off at Prudential Centre, Nathan Road. Your hotel is right on the opposite. It is quite convenient and is within walking distance to Jordan Station. Just consider not changing it. In addition, you have another option: take Airport Express to Kowloon and transfer to free bus line K1. Get off at the first stop - Jordan Station (Austin Road) and walk to your hotel.