Timing Chain Replacement - 2002 Sentra QG18DE

[02_Sentra]

I have low compression in one cylinder (#3), on a 2002 Nissan Sentra (QG18DE). Pressure at the cylinder is only 30PSI, which leads me to believe it is a stuck valve. I've already replaced the head gasket once and didn't bother to rebuild the head while it was out (dumb mistake on my part). Question for someone. I'll also be replacing the timing chain this time around. When I did the head gasket 43K miles ago, the timing chain wasn't removed, so the car maintained the proper timing. Is there anything I need to be aware of when replacing the timing chain? More so, how will the 'mating' marks line up if it's a whole new chain altogether? Oh, I almost forgot; any suggestions on where to find a decently priced timing chain kit? I'm looking at Cloyes 9-0724S (which is the part for this particular engine/year)? Would anyone suggest those cheaply priced kits available on ebay?! I'm looking forward to tackling this job within the next day or two (at least removing the head and taking it to a machine shop). Any help would be greatly appreciated! Thanks!!