Replacing the water pump along with the chains is a good idea on any VQ. The job is doable but difficult with the engine in. The rear cover is an engine-out job but isn't necessary just to replace chains. The rocker covers do need to come off for chain replacement, and on a '13 new ones and a fresh PCV Valve and hose will be a good idea -- especially the hose, since a collapsed one will sludge and ruin your engine. The complete TC kit should include all three chains, tensioners, guide shoes, both front cover o-rings, and a new crank seal.
See what's involved starting on EM-54 here:
https://www.nicoclub.com/service-manual ... 3%2FEM.pdf