Is it an automatic or manual transmission? I only ask because if it's a manual 6 speed you would use either Nissan MTF 75W-80 or as an alternative.. Use API GL-4 SAE 75W-80.
If you have an auto trans, you'd need Nissan Matic S. I know Amzoil and Castrol/Valvoline blah blah work just as well. If you're at 60K, I'm going to assume that's a factory fill thus the Matic S recommendation.
Any ATF that is recommended for NissanMatic Type "J" or "S" ATF applications will work. The two popular choices are Valvoline Maxlife Full-synthetic ATF and Castrol Transmax Import Multi-vehicle ATF. I use the Valvoline which I get for $18/gallon jug at Walmart which is perfect for a drain and fill. I have a combined 260,000 miles of use between two, R51 Pathfinders using the Valvoline Maxlife and they both shift like when I first got them. I also use in in my 2003 Frontier.
If you want OEM but also want to avoid the dealer (can't blame you there), you can get genuine Nissan fluids and parts on eBay at reasonable prices, often sold by honest Nissan dealers at a discount. I see 5 quarts for $52 right now on there.
I see that it's easy to get Nissan OEM oil filters as well, I'll probably buy a handful of them for oil changes. Might as well use OEM parts when possible.
Just to add to the advice above, I know the manual for our 2017 states Matic- J can be used for the 5spd auto, but Matic-S is the preferred. This Jatco 5spd auto has been around for a long time and holds up well. I personally wouldn't sweat using a suitable aftermarket ATF at all in them, especially given how easy they are to drain/fill. It's basically easier than an engine oil change on these trucks.