hello all new to site oil problem 06

hello all. I have a 2006 nissan frontier and am having problems.

I was driving along...all was fine....oil light flickered on and truck lost power....I pulled over, truck stalled and wouldnt' start.
I had it towed to garage... left it for the weekend. and on the monday started it, it seemd to run fine but oil pressure seemed very low.
I had the oil changed...it was very dirty,
Truck will now start and run for a few mins and then will making a ticking/knocking sound.

A few things come to mind but I'm at a loss? oil pump? plugged oil pick up in oil pan?

any help or suggestions would be great.

Thanks in advance.